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>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index e12a03c..dd27b07 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -304,14 +304,13 @@
 	return ret;
 }
 
-static int mmc_blk_release(struct gendisk *disk, fmode_t mode)
+static void mmc_blk_release(struct gendisk *disk, fmode_t mode)
 {
 	struct mmc_blk_data *md = disk->private_data;
 
 	mutex_lock(&block_mutex);
 	mmc_blk_put(md);
 	mutex_unlock(&block_mutex);
-	return 0;
 }
 
 static int