ray_cs: Check return value of pcmcia_register_driver

init_ray_cs does not check value of pcmcia_register_driver,
if it fails, there maybe cause a NULL pointer dereference in
exit_ray_cs.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ray_cs.c

@@ -2795,6 +2795,8 @@ static int __init init_ray_cs(void)
 	rc = pcmcia_register_driver(&ray_driver);
 	pr_debug("raylink init_module register_pcmcia_driver returns 0x%x\n",
 	      rc);
+	if (rc)
+		return rc;
 
 #ifdef CONFIG_PROC_FS
 	proc_mkdir("driver/ray_cs", NULL);