fs/fscache/stats.c: fix memory leak

There is a kernel memory leak observed when the proc file
/proc/fs/fscache/stats is read.

The reason is that in fscache_stats_open, single_open is called and the
respective release function is not called during release.  Hence fix
with correct release function - single_release().

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=57101

Signed-off-by: Anurup m <anurup.m@huawei.com>
Cc: shyju pv <shyju.pv@huawei.com>
Cc: Sanil kumar <sanil.kumar@huawei.com>
Cc: Nataraj m <nataraj.m@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fscache/stats.c

@@ -287,5 +287,5 @@ const struct file_operations fscache_stats_fops = {
 	.open		= fscache_stats_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
-	.release	= seq_release,
+	.release        = single_release,
 };