[PATCH] v4l: 721: check kthread correctly

- Check ->kthread correctly
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Michael Krufky <mkrufky@m1k.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/media/video/msp3400.c

@@ -1566,7 +1566,7 @@ static int msp_detach(struct i2c_client *client)
 	struct msp3400c *msp  = i2c_get_clientdata(client);
 
 	/* shutdown control thread */
-	if (msp->kthread >= 0) {
+	if (msp->kthread) {
 		msp->restart = 1;
 		kthread_stop(msp->kthread);
 	}