gpio/omap: cleanup set_gpio_triggering function

Getting rid of ifdefs within the function by adding register offset intctrl
and associating OMAPXXXX_GPIO_INT_CONTROL in respective SoC specific files.
Also, use wkup_status register consistently instead of referring to wakeup
clear and wakeup set register offsets. Get rid of cpu_is_xxxx checks in
set_gpio_trigger() using irqctrl.

Signed-off-by: Charulatha V <charu@ti.com>
Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap1/gpio15xx.c

@@ -42,6 +42,7 @@ static struct omap_gpio_reg_offs omap15xx_mpuio_regs = {
 	.irqstatus	= OMAP_MPUIO_GPIO_INT,
 	.irqenable	= OMAP_MPUIO_GPIO_MASKIT,
 	.irqenable_inv	= true,
+	.irqctrl	= OMAP_MPUIO_GPIO_INT_EDGE,
 };
 
 static struct __initdata omap_gpio_platform_data omap15xx_mpu_gpio_config = {
@@ -83,6 +84,7 @@ static struct omap_gpio_reg_offs omap15xx_gpio_regs = {
 	.irqstatus	= OMAP1510_GPIO_INT_STATUS,
 	.irqenable	= OMAP1510_GPIO_INT_MASK,
 	.irqenable_inv	= true,
+	.irqctrl	= OMAP1510_GPIO_INT_CONTROL,
 };
 
 static struct __initdata omap_gpio_platform_data omap15xx_gpio_config = {