LU-18030 llite: make ll_set_acl send xattr to server unmodified

LU-18030 llite: make ll_set_acl send xattr to server unmodified

Otherwise posix_acl_update_mode might convert acl into inode mode
change and as the result it's lost and the existing ACL xattr
is removed (if any

Change-Id: I3956beac04889a657f76f9b36dbe97518ae9f2ac
Signed-off-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55715
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>