drivers: input: Fix OMAP_GPIO_IRQ with gpio_to_irq() in ams_delta_serio_exit()

Even though ams-delta-serio input driver uses gpio_to_irq() in all
relevent places to get irq number, the ams_delta_serio_exit() still
uses OMAP_GPIO_IRQ macro. Fix this.

Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Tony Lindgren <tony@atomide.com>