drm/radeon: Convert logging in radeon_display.c to drm_* helpers

drm/radeon: Convert logging in radeon_display.c to drm_* helpers

Replace DRM_ERROR() and DRM_INFO() calls in
drivers/gpu/drm/radeon/radeon_display.c with the corresponding
drm_err() and drm_info() helpers.

The drm_*() logging functions take a struct drm_device * argument,
allowing the DRM core to prefix log messages with the correct device
name and instance. This is required to correctly distinguish log
messages on systems with multiple GPUs.

This change aligns radeon with the DRM TODO item:
"Convert logging to drm_* functions with drm_device parameter".

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Mukesh Ogare <mukeshogare871@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>