LU-14073 ldiskfs: don't test LDISKFS_IOC_FSSETXATTR

LU-14073 ldiskfs: don't test LDISKFS_IOC_FSSETXATTR

EXT4_IOC_FSSETXATTR was removed upstream in Linux 5.9, Commit
cb29a02d3a9d ("ext4: use generic names for generic ioctls").
So we cannot use it to test if project quotas are supported.

Instead test if EXT4_MAXQUOTAS is 3.  This was changed to 3 upstream
in the commit immediately before EXT4_IOC_FSSETXATTR was added, so it
is effectively the same test.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I88c51c03959ebe98cd5066596f5158fac570a625
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49353
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>