This replaces the placeholder ZFS_PROP_PRIVATE with ZFS_PROP_ACLMODE,
matching what is done in the NFSv4 ACLs PR (#9709).
On FreeBSD we hide ZFS_PROP_ACLTYPE, while on Linux we hide
ZFS_PROP_ACLMODE.
The tests already assume this arrangement.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#9913