smbd: split out smbd_check_access_rights_fname and call it before SMB_VFS_FGET_NT_ACL

smbd: split out smbd_check_access_rights_fname and call it before SMB_VFS_FGET_NT_ACL

commit 8e3798dd22276bc1ac8e96004d0e5e974240a7b9 actually came with a
change in behavior..., as SMB_VFS_GET_NT_ACL_AT() (at the time) and
now SMB_VFS_FGET_NT_ACL() is always called even if it's not needed.
E.g. access by root.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Tue Jul 26 00:31:29 UTC 2022 on sn-devel-184