gpio: pxa: change the interrupt management

The interrupt management is changed by this patch to rely on chip data
instead of chained interrupts.

The main goal is to loosen the dependency on the global pxa chip
structure in favor of the passed chip data. The secondary goal is to
better show in /proc/interrupts the difference between interrupts for
gpio0 and gpio1 (directly wired to interrupt controller), and the other
gpios (wired onto a third line in the interrupt controller).

The last advantage of this patch is that the interrupt is actually
requested, so that another driver cannot steal this line, or overwrite
the handler.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>