ext4: add EXT4_INODE_HAS_XATTR_SPACE macro in xattr.h

hulk inclusion
category: bugfix
bugzilla: 186866, https://gitee.com/openeuler/kernel/issues/I5DTBL


CVE: NA

--------------------------------

When adding an xattr to an inode, we must ensure that the inode_size is
not less than EXT4_GOOD_OLD_INODE_SIZE + extra_isize + pad. Otherwise,
the end position may be greater than the start position, resulting in UAF.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>