drm/komeda: Add komeda_crtc_atomic_enable/disable

Pass enable/disable command to komeda and adjust komeda hardware for
enable/disable a display instance.

v2: Rebase

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>