gpio: bcm-kona: lock IRQs when starting them

This uses the new API for tagging GPIO lines as in use by
IRQs. This enforces a few semantic checks on how the underlying
GPIO line is used.

Cc: Christian Daudt <csd@broadcom.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Tested-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>