As per the re-design assign the first bank regs for unbanked
irq case. This was missed out in the original patch.
Signed-off-by: NKeerthy <j-keerthy@ti.com>
Fixes: b5cf3fd8 ("gpio: davinci: Redesign driver to accommodate ngpios in one gpio chip")
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>