gpio/omap: conslidate enable/disable of GPIO IRQs, remove ifdefs

Cleanup GPIO IRQ enable/disable handling by removing SoC-specific

Also split enable/disable IRQ into separate functions for better
readability and also facilitate potentially moving to generic irq_chip
in the future.

Signed-off-by: Kevin Hilman <khilman@ti.com>
diff --git a/arch/arm/mach-omap1/gpio15xx.c b/arch/arm/mach-omap1/gpio15xx.c
index 487a087..9175624 100644
--- a/arch/arm/mach-omap1/gpio15xx.c
+++ b/arch/arm/mach-omap1/gpio15xx.c
@@ -39,6 +39,8 @@
 	.datain		= OMAP_MPUIO_INPUT_LATCH,
 	.dataout	= OMAP_MPUIO_OUTPUT,
 	.irqstatus	= OMAP_MPUIO_GPIO_INT,
+	.irqenable	= OMAP_MPUIO_GPIO_MASKIT,
+	.irqenable_inv	= true,
 };
 
 static struct __initdata omap_gpio_platform_data omap15xx_mpu_gpio_config = {
@@ -77,6 +79,8 @@
 	.datain		= OMAP1510_GPIO_DATA_INPUT,
 	.dataout	= OMAP1510_GPIO_DATA_OUTPUT,
 	.irqstatus	= OMAP1510_GPIO_INT_STATUS,
+	.irqenable	= OMAP1510_GPIO_INT_MASK,
+	.irqenable_inv	= true,
 };
 
 static struct __initdata omap_gpio_platform_data omap15xx_gpio_config = {