staging: wilc1000: fix static checker warning to unlock mutex in wilc_deinit()

Fix for static checker warning inconsistent returns of
'hif_deinit_lock'(more details [1]).

"drivers/staging/wilc1000/host_interface.c:3390 wilc_deinit()
              warn: inconsistent returns 'hif_deinit_lock'."

Fixes: ff52a57a ("staging: wilc1000: move the allocation of cmd out
of wilc_enqueue_cmd()")

[1]. https://www.spinics.net/lists/linux-driver-devel/msg114216.htmlReported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/host_interface.c

@@ -3370,15 +3370,15 @@ int wilc_deinit(struct wilc_vif *vif)
 		struct host_if_msg *msg;
 
 		msg = wilc_alloc_work(vif, handle_hif_exit_work, true);
-		if (IS_ERR(msg))
-			return PTR_ERR(msg);
-
-		result = wilc_enqueue_work(msg);
-		if (result)
-			netdev_err(vif->ndev, "deinit : Error(%d)\n", result);
-		else
-			wait_for_completion(&msg->work_comp);
-		kfree(msg);
+		if (!IS_ERR(msg)) {
+			result = wilc_enqueue_work(msg);
+			if (result)
+				netdev_err(vif->ndev, "deinit : Error(%d)\n",
+					   result);
+			else
+				wait_for_completion(&msg->work_comp);
+			kfree(msg);
+		}
 		destroy_workqueue(hif_workqueue);
 	}