Revert "drm/amdgpu: use dirty framebuffer helper"

This reverts commit 66f99628.

Unfortunately, that commit causes performance regressions on non-PSR
setups. So, just revert it until FB_DAMAGE_CLIPS support can be added.

Cc: stable@vger.kernel.org
Link: drm/amd#2189


Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>