drm/i915/guc: reserve the doorbell before selecting the cacheline

Cacheline selection is only needed if we actually manage to reserve a
doorbell.

Cc: Michal Wajdeczko <[e-mail]>
Reviewed-by: Michal Wajdeczko <[e-mail]>
Signed-off-by: Daniele Ceraolo Spurio <[e-mail]>
Signed-off-by: Chris Wilson <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/intel_guc_submission.c

···
 	}
 	client->vaddr = vaddr;
 
+	ret = reserve_doorbell(client);
+	if (ret)
+		goto err_vaddr;
+
 	client->doorbell_offset = __select_cacheline(guc);
 
 	/*
···
 		client->proc_desc_offset = 0;
 	else
 		client->proc_desc_offset = (GUC_DB_SIZE / 2);
-
-	ret = reserve_doorbell(client);
-	if (ret)
-		goto err_vaddr;
 
 	DRM_DEBUG_DRIVER("new priority %u client %p for engine(s) 0x%x: stage_id %u\n",
 			 priority, client, client->engines, client->stage_id);