mfd: Convert AB8500 to new irq_ methods

The genirq core is being converted to supply struct irq_data to chips
rather than the interrupt number.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>