This reverts commit ca3b3faf.

There was a plan to place ab8500_irq_get_virq() calls in each AB8500
child device prior to requesting an IRQ, but as we're no longer using
Device Tree to collect our IRQ numbers, it's actually better to allow
the core to do this during device registration time. So the IRQ number
we pull from its resource has already been converted to a virtual IRQ.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>