drm: mali-dp: Disable planes when their CRTC gets disabled.

Make sure only the planes on the active CRTCs get committed and
that all planes on the disabled CRTCs get turned off.
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

drivers/gpu/drm/arm/malidp_crtc.c

@@ -77,6 +77,9 @@ static void malidp_crtc_atomic_disable(struct drm_crtc *crtc,
 	struct malidp_hw_device *hwdev = malidp->dev;
 	int err;
 
+	/* always disable planes on the CRTC that is being turned off */
+	drm_atomic_helper_disable_planes_on_crtc(old_state, false);
+
 	drm_crtc_vblank_off(crtc);
 	hwdev->hw->enter_config_mode(hwdev);