mfd: Add irq domain support for max8997 interrupts

Add irq domain support for max8997 interrupts. The reverse mapping method
used is linear mapping since the sub-drivers of max8997 such as regulator
and charger drivers can use the max8997 irq_domain to get the linux irq
number for max8997 interrupts. All uses of irq_base in platform data and
max8997 driver private data are removed.

Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

arch/arm/mach-exynos/mach-nuri.c

@@ -1067,12 +1067,8 @@ static struct platform_device nuri_max8903_device = {
 static void __init nuri_power_init(void)
 {
 	int gpio;
-	int irq_base = IRQ_GPIO_END + 1;
 	int ta_en = 0;
 
-	nuri_max8997_pdata.irq_base = irq_base;
-	irq_base += MAX8997_IRQ_NR;
-
 	gpio = EXYNOS4_GPX0(7);
 	gpio_request(gpio, "AP_PMIC_IRQ");
 	s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(0xf));