gpio: omap: drop 'gpio' param from omap_gpio_init_irq()

gpio: omap: drop 'gpio' param from omap_gpio_init_irq()

The 'gpio' parameter isn't needed any more as it
duplicates 'offset' parameter, so drop it.

Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Acked-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>