netfs: Prevent duplicate unlocking

[ Upstream commit 66d938e8 ]

The filio lock has been released here, so there is no need to jump to
error_folio_unlock to release it again.

Reported-by:  <syzbot+b73c7d94a151e2ee1e9b@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=b73c7d94a151e2ee1e9b


Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>