Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:202: warning: Function parameter or member 'hwmgr' not described in 'smu7_get_mc_microcode_version'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:242: warning: Function parameter or member 'hwmgr' not described in 'smu7_enable_smc_voltage_controller'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:263: warning: Function parameter or member 'hwmgr' not described in 'smu7_voltage_control'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:277: warning: Function parameter or member 'hwmgr' not described in 'smu7_enable_voltage_control'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:315: warning: Function parameter or member 'hwmgr' not described in 'smu7_construct_voltage_tables'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:428: warning: Function parameter or member 'hwmgr' not described in 'smu7_program_static_screen_threshold_parameters'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:450: warning: Function parameter or member 'hwmgr' not described in 'smu7_enable_display_gap'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:474: warning: Function parameter or member 'hwmgr' not described in 'smu7_program_voting_clients'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:570: warning: Function parameter or member 'hwmgr' not described in 'smu7_initial_switch_from_arbf0_to_f1'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:1926: warning: Function parameter or member 'hwmgr' not described in 'smu7_get_evv_voltages'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2028: warning: Function parameter or member 'hwmgr' not described in 'smu7_patch_ppt_v1_with_vdd_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2028: warning: Function parameter or member 'voltage' not described in 'smu7_patch_ppt_v1_with_vdd_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2028: warning: Function parameter or member 'leakage_table' not described in 'smu7_patch_ppt_v1_with_vdd_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2056: warning: Function parameter or member 'hwmgr' not described in 'smu7_patch_lookup_table_with_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2056: warning: Function parameter or member 'lookup_table' not described in 'smu7_patch_lookup_table_with_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2056: warning: Function parameter or member 'leakage_table' not described in 'smu7_patch_lookup_table_with_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2511: warning: Function parameter or member 'hwmgr' not described in 'smu7_patch_ppt_v0_with_vdd_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2511: warning: Function parameter or member 'voltage' not described in 'smu7_patch_ppt_v0_with_vdd_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:2511: warning: Function parameter or member 'leakage_table' not described in 'smu7_patch_ppt_v0_with_vdd_leakage'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4449: warning: Function parameter or member 'hwmgr' not described in 'smu7_program_display_gap'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4508: warning: Function parameter or member 'hwmgr' not described in 'smu7_set_max_fan_rpm_output'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4508: warning: Function parameter or member 'us_max_fan_rpm' not described in 'smu7_set_max_fan_rpm_output'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4707: warning: Function parameter or member 'hwmgr' not described in 'smu7_get_memory_type'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4723: warning: Function parameter or member 'hwmgr' not described in 'smu7_enable_acpi_power_management'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4737: warning: Function parameter or member 'hwmgr' not described in 'smu7_init_power_gate_state'

Cc: Evan Quan <evan.quan@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>