drm/amd/display: Convert some legacy DRM debug macros into appropriate categories

Currently when one enables driver debugging dmesg gets spammed, at I
suspect vblank rate, with messages like:

 [drm:amdgpu_dm_atomic_check [amdgpu]] MPO enablement requested on crtc:[00000000f073c3bb]

Fix if by converting some logging from deprecated and incorrect
DRM_DEBUG_DRIVER to drm_dbg_atomic. Plus some localized drive-by changes
to drm_dbg_kms.

By no means an exhaustive conversion but at least it allows turning on
driver debug selectively.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>