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

 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:115: warning: Function parameter or member 'adev' not described in 'amdgpu_virt_request_full_gpu'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:115: warning: Excess function parameter 'amdgpu' description in 'amdgpu_virt_request_full_gpu'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:138: warning: Function parameter or member 'adev' not described in 'amdgpu_virt_release_full_gpu'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:138: warning: Excess function parameter 'amdgpu' description in 'amdgpu_virt_release_full_gpu'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:159: warning: Function parameter or member 'adev' not described in 'amdgpu_virt_reset_gpu'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:159: warning: Excess function parameter 'amdgpu' description in 'amdgpu_virt_reset_gpu'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:194: warning: Function parameter or member 'adev' not described in 'amdgpu_virt_wait_reset'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:194: warning: Excess function parameter 'amdgpu' description in 'amdgpu_virt_wait_reset'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:210: warning: Function parameter or member 'adev' not described in 'amdgpu_virt_alloc_mm_table'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:210: warning: Excess function parameter 'amdgpu' description in 'amdgpu_virt_alloc_mm_table'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:239: warning: Function parameter or member 'adev' not described in 'amdgpu_virt_free_mm_table'
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:239: warning: Excess function parameter 'amdgpu' description in 'amdgpu_virt_free_mm_table'
Acked-by: Christian König <christian.koenig@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>