compat_blkdev_driver_ioctl: Remove unused variable warning

Variable 'ret' is no longer used. Don't declare it.

Signed-off-by: Linus Torvalds <[e-mail]>

block/compat_ioctl.c

···
 static int compat_blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 			unsigned cmd, unsigned long arg)
 {
-	int ret;
-
 	switch (cmd) {
 	case HDIO_GET_UNMASKINTR:
 	case HDIO_GET_MULTCOUNT: