drm/amd/amdgpu: Fix style errors in amdgpu_display.c

Fix following checkpatch errors in amdgpu_display.c

ERROR: spaces required around that '=' (ctx:VxW)
ERROR: that open brace { should be on the previous line
ERROR: else should follow close brace '}'

Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>