gpio: omap: initialize gpioirq chip as part of gpiochip_add_data

gpio: omap: initialize gpioirq chip as part of gpiochip_add_data

Hence, series from Thierry Reding [1] merged - the OMAP GPIO driver can be
switched to reuse new feature and just fill new struct gpio_irq_chip before
calling gpiochip_add_data() instead of using few separate gpioirq chip
APIs. gpiochip_add_data() will do the job and create and initialize gpioirq
chip

[1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1531592.html

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>