This patch fixes a check for offset in gpio_to_irq_unbanked()
and also assigns gpio_irq, gpio_unbanked of chips[0] to
appropriate values which is used in gpio_to_irq_unbanked()
function.

Without this patch, unbanked IRQ handling is broken.
Reported-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Acked-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NSekhar Nori <nsekhar@ti.com>