ksmbd: change security id to the one samba used for posix extension

[ Upstream commit 5609bdd9 ]

Samba set SIDOWNER and SIDUNIX_GROUP in create posix context and
set SIDUNIX_USER/GROUP in other sids for posix extension.
This patch change security id to the one samba used.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>