pinctrl/abx500: replace IRQ offsets with table read-in values

pinctrl/abx500: replace IRQ offsets with table read-in values

The ABx500 GPIO controller used to provide a set of virtual contiguous
IRQs for use by sub-devices, but they have been removed after a request
from Mainline Maintainers. Now the AB8500 core driver deals with almost
all IRQ related issues instead.

The ABx500 GPIO driver is now only used to convert between GPIO and IRQ
numbers which is actually quite difficult, as the ABx500 GPIO's
associated IRQs are clustered together throughout the interrupt number
space at irregular intervals. To solve this quandary, we have placed the
read-in values into the existing cluster information table to use during
conversion.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
[Moved irq_base removal into this patch]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>