xfs: reduce the size of struct xfs_extent_free_item

mainline inclusion
from mainline-v5.15-rc4
commit b3b5ff41
category: bugfix
bugzilla: 188883, https://gitee.com/openeuler/kernel/issues/I76JSK
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b3b5ff412ab04afd99173bb12d3cc146ee478ae7



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

We only use EFIs to free metadata blocks -- not regular data/attr fork
extents.  Remove all the fields that we never use, for a net reduction
of 16 bytes.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Long Li <leo.lilong@huawei.com>