Staging: pohmelfs/dir.c: Remove unneeded mutex_unlock() from pohmelfs_rename()

I do not see any reason for the mutex_unlock(&inode->i_mutex); in
pohmelfs_rename().

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/pohmelfs/dir.c

@@ -1082,7 +1082,6 @@ static int pohmelfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 
 	clear_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state);
 
-	mutex_unlock(&inode->i_mutex);
 	return err;
 }