gpio: max732x: fix input configuration for open-drain pins

Fix a bug I noticed while hacking on the max732x driver for interrupt
support.  According to the datasheets, open-drain pins have to be
configured as output-high (which in that case is actually high impedance)
to be used as input.

Signed-off-by: Marc Zyngier <maz@misterjones.org>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>