gpio_cs5535: disable AUX on output

The AMD CS5535/CS5536 GPIO has two alternate output modes: AUX-1 and AUX-2.
When either AUX is enabled, the cs5535_gpio driver cannot control the
output.

Some BIOS code for the Geode processor enables AUX-1 for GPIO-1, which
configures it as the PC BEEP output.

This patch will disable AUX-1 and AUX-2 when the user enables output.

Signed-of-by: Ben Gardner <gardner.ben@gmail.com>
Cc: Richard Knutsson <ricknu-0@student.ltu.se>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>