ext4: fix iloc.bh leak in ext4_xattr_inode_update_ref

ext4: fix iloc.bh leak in ext4_xattr_inode_update_ref

The error branch for ext4_xattr_inode_update_ref forget to release the
refcount for iloc.bh. Find this when review code.

Fixes: 57295e835408 ("ext4: guard against EA inode refcount underflow in xattr update")
Signed-off-by: Yang Erkun <yangerkun@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20251213055706.3417529-1-yangerkun@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org