drm/amd/display: convert more DRM_ERROR to drm_err

drm/amd/display: convert more DRM_ERROR to drm_err

prefer drm_err instead of DRM_ERROR since the former prints the
associated DRM device, which is helpful when debugging multi-gpu
use cases.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>