[media] rc_core: avoid kernel oops when rmmod saa7134

The following is a patch to avoid a kernel oops when running rmmod
saa7134 on kernel 2.6.27.1. The change is as suggested by mchehab on
irc.freenode.org
Signed-off-by: NHussam Al-Tayeb <ht990332@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/rc/rc-main.c

@@ -707,7 +707,8 @@ static void ir_close(struct input_dev *idev)
 {
 	struct rc_dev *rdev = input_get_drvdata(idev);
 
-	rdev->close(rdev);
+	 if (rdev)
+		rdev->close(rdev);
 }
 
 /* class for /sys/class/rc */