cifs: reinstate original behavior again for forceuid/forcegid

forceuid/forcegid should be enabled by default when uid=/gid= options are
specified, but commit 24e0a1ef ("cifs: switch to new mount api")
changed the behavior. Due to the change, a mounted share does not show
intentional uid/gid for files and directories even though uid=/gid=
options are specified since forceuid/forcegid are not enabled.

This patch reinstates original behavior that overrides uid/gid with
specified uid/gid by the options.

Fixes: 24e0a1ef

 ("cifs: switch to new mount api")
Signed-off-by: Takayuki Nagata <tnagata@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Acked-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Steve French <stfrench@microsoft.com>