ARM: ux500: use real AB8500 IRQ numbers instead of virtual ones

Any devices wishing to use the AB8500's GPIO IRQs were forced to
request virtual IRQs from the gpio-ab8500 driver. Now that
responsibility has been passed back to the AB8500 core driver,
devices can request real IRQ numbers instead. This patch removes
any traces of the old virtual IRQ conversion handlers, which will
force any drivers requesting IRQs to use real IRQS.

Cc: arm@kernel.org
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>