drm/i915/guc: Process all G2H message at once in work queue

Rather than processing 1 G2H at a time and re-queuing the work queue if
more messages exist, process all the G2H in a single pass of the work
queue.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-6-matthew.brost@intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c

@@ -1042,9 +1042,9 @@ static void ct_incoming_request_worker_func(struct work_struct *w)
 		container_of(w, struct intel_guc_ct, requests.worker);
 	bool done;
 
-	done = ct_process_incoming_requests(ct);
-	if (!done)
-		queue_work(system_unbound_wq, &ct->requests.worker);
+	do {
+		done = ct_process_incoming_requests(ct);
+	} while (!done);
 }
 
 static int ct_handle_event(struct intel_guc_ct *ct, struct ct_incoming_msg *request)