LU-18360 zfs-osd: za_name flexible array

LU-18360 zfs-osd: za_name flexible array

zfs-2.3 commit 3cf2bfa57008af7f0690f73491d7f9b4ac4ed65a
  Allocate zap_attribute_t from kmem instead of stack

za_name maximum size increased to ZAP_MAXNAMELEN_NEW

Ensure zap_attribute_t.za_name space is available and
zap_attribute_t.za_name_len now needs to be initialized
to the allocated space of MAXNAMELEN.

Also mkfs should disable longname support as it would break
MAX_NAME interop.

HPE-bug-id: LUS-12561
Test-Parameters: fstype=zfs
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I6c48c66a42a36ea6816b37ffce7e17f45eed3dbf
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56656
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>