mfd: da9063: Add IRQ support

This patch adds a regmap irqchip for DA9063 IRQs. It depends on

  git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git

 tags/regmap-irq-ack-mask

Signed-off-by: Krystian Garbaciak <krystian.garbaciak@diasemi.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>