drm/i915/psr: Clear frontbuffer busy bits on flip

We are planning to move flush performed from work queue. This
means it is possible to have invalidate -> flip -> flush sequence.
Handle this by clearing possible busy bits on flip.

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230901093500.3463046-3-jouni.hogander@intel.com

drivers/gpu/drm/i915/display/intel_psr.c

@@ -2230,6 +2230,12 @@ static void _intel_psr_post_plane_update(const struct intel_atomic_state *state,
 		if (crtc_state->crc_enabled && psr->enabled)
 			psr_force_hw_tracking_exit(intel_dp);
 
+		/*
+		 * Clear possible busy bits in case we have
+		 * invalidate -> flip -> flush sequence.
+		 */
+		intel_dp->psr.busy_frontbuffer_bits = 0;
+
 		mutex_unlock(&psr->lock);
 	}
 }