media: saa7164: fix return value check in saa7164_initdev()

commit 89f4d45b upstream.

In case of error, the function kthread_run() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/media/video/saa7164/saa7164-core.c

@@ -1386,9 +1386,11 @@ static int __devinit saa7164_initdev(struct pci_dev *pci_dev,
 		if (fw_debug) {
 			dev->kthread = kthread_run(saa7164_thread_function, dev,
 				"saa7164 debug");
-			if (!dev->kthread)
+			if (IS_ERR(dev->kthread)) {
+				dev->kthread = NULL;
 				printk(KERN_ERR "%s() Failed to create "
 					"debug kernel thread\n", __func__);
+			}
 		}
 
 	} /* != BOARD_UNKNOWN */