gpio/omap: convert gpio irq domain to linear mapping

gpio/omap: convert gpio irq domain to linear mapping

Currently the OMAP GPIO driver uses a legacy mapping for the GPIO IRQ
domain. This is not necessary because we do not need to assign a
specific interrupt number to the GPIO IRQ domain. Therefore, convert
the OMAP GPIO driver to use a linear mapping instead.

Please note that this also allows to simplify the logic in the OMAP
gpio_irq_handler() routine, by using irq_find_mapping() to obtain the
virtual irq number from the GPIO bank and bank index.

Reported-by: Linus Walleij <[email protected]>
Signed-off-by: Jon Hunter <[email protected]>
Reviewed-by: Felipe Balbi <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Kevin Hilman <[email protected]>
Tested-by: Javier Martinez Canillas <[email protected]>
Signed-off-by: Grant Likely <[email protected]>