[PATCH] uidgid: Make uid_valid and gid_valid work with !CONFIG_MULTIUSER

{u,g}id_valid call {u,g}id_eq, which calls __k{u,g}id_val on both arguments and compares. With !CONFIG_MULTIUSER, __k{u,g}id_val return a constant 0, which makes {u,g}id_valid always return false. Change {u,g}id_valid to compare their argument against -1 instead. That produces identical results

[PATCH] uidgid: Make uid_valid and gid_valid work with !CONFIG_MULTIUSER

{u,g}id_valid call {u,g}id_eq, which calls __k{u,g}id_val on both arguments and compares. With !CONFIG_MULTIUSER, __k{u,g}id_val return a constant 0, which makes {u,g}id_valid always return false. Change {u,g}id_valid to compare their argument against -1 instead. That produces identical results