drm/amd/display: Clean up some inconsistent indenting

No functional modification involved.

smatch warning:

drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_dwb.c:104 dwb2_enable() warn: inconsistent indenting.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>