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

 In file included from drivers/gpu/drm/amd/amdgpu/../display/dc/dce110/dce110_resource.c:66:
 drivers/gpu/drm/amd/amdgpu/../include/asic_reg/dce/dce_11_0_sh_mask.h:5936:51: warning: initialized field overwritten [-Woverride-init]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_stream_encoder.h:116:16: note: in expansion of macro ‘DIG_FE_CNTL__DIG_STEREOSYNC_SELECT__SHIFT’
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_stream_encoder.h:306:2: note: in expansion of macro ‘SE_SF’
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce110/dce110_resource.c:272:3: note: in expansion of macro ‘SE_COMMON_MASK_SH_LIST_DCE110’
 drivers/gpu/drm/amd/amdgpu/../include/asic_reg/dce/dce_11_0_sh_mask.h:5936:51: note: (near initialization for ‘se_shift.DIG_STEREOSYNC_SELECT’)
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_stream_encoder.h:116:16: note: in expansion of macro ‘DIG_FE_CNTL__DIG_STEREOSYNC_SELECT__SHIFT’
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_stream_encoder.h:306:2: note: in expansion of macro ‘SE_SF’
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce110/dce110_resource.c:272:3: note: in expansion of macro ‘SE_COMMON_MASK_SH_LIST_DCE110’
 drivers/gpu/drm/amd/amdgpu/../include/asic_reg/dce/dce_11_0_sh_mask.h:5938:52: warning: initialized field overwritten [-Woverride-init]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_stream_encoder.h:116:16: note: in expansion of macro ‘DIG_FE_CNTL__DIG_STEREOSYNC_GATE_EN__SHIFT’
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_stream_encoder.h:307:2: note: in expansion of macro ‘SE_SF’
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce110/dce110_resource.c:272:3: note: in expansion of macro ‘SE_COMMON_MASK_SH_LIST_DCE110’
 drivers/gpu/drm/amd/amdgpu/../include/asic_reg/dce/dce_11_0_sh_mask.h:5938:52: note: (near initialization for ‘se_shift.DIG_STEREOSYNC_GATE_EN’)

 NB: Snipped for brevity

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@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>