[ARM] pxa/spitz: convert to use new GPIO API

Original patch from Dmitry Baryshkov's initial scoop gpio conversion
work at http://git.infradead.org/users/dbaryshkov/zaurus-2.6.git.

Separated into this dedicated generic GPIO conversion patch for the
work of deprecating pxa_gpio_mode().

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>