ARM: 8233/1: sa1100: switch to hwirq usage

Switch internally to using hardware irq numbers (hwirq). In case of GPIO
interrupts, hwirq is equal to GPIO number. In case of system interrupts,
hwirq is equal to interrupt number in the interrupt controller.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>