Fixes the following gcc with W=1:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:374: warning: Function parameter or member 'dc' not described in 'update_planes_and_stream_adapter'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:374: warning: Function parameter or member 'update_type' not described in 'update_planes_and_stream_adapter'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:374: warning: Function parameter or member 'planes_count' not described in 'update_planes_and_stream_adapter'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:374: warning: Function parameter or member 'stream' not described in 'update_planes_and_stream_adapter'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:374: warning: Function parameter or member 'stream_update' not described in 'update_planes_and_stream_adapter'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:374: warning: Function parameter or member 'array_of_surface_update' not described in 'update_planes_and_stream_adapter'

Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>