[MIPS] au1000: Make sure GPIO value is zero or one

David Brownell <david-b@pacbell.net> wrote:
>       The problem is that "value" is zero-or-nonzero.
>       This code wrongly assumes it's zero-or-one.
>       Possible fix:  "((!!value) << gpio)".

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>