Draft: drm/amdkfd: bring MEMORY_DEVICE_COHERENT handling to upstream level
JIRA: https://issues.redhat.com/browse/RHEL-53530
Because of different backport targets in history of DRM and MM,
MEMORY_DEVICE_COHERENT support has evolved in different phases
in those two subsystems. Bring amdkfd MEMORY_DEVICE_COHERENT
support to same level as upstream.
Signed-off-by: Mika Penttilä mpenttil@redhat.com