block_device_operations->release() should return void

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/xtensa/platforms/iss/simdisk.c

@@ -139,13 +139,12 @@ static int simdisk_open(struct block_device *bdev, fmode_t mode)
 	return 0;
 }
 
-static int simdisk_release(struct gendisk *disk, fmode_t mode)
+static void simdisk_release(struct gendisk *disk, fmode_t mode)
 {
 	struct simdisk *dev = disk->private_data;
 	spin_lock(&dev->lock);
 	--dev->users;
 	spin_unlock(&dev->lock);
-	return 0;
 }
 
 static const struct block_device_operations simdisk_ops = {