ARM: imx: eliminate macro IOMUX_TO_IRQ()

ARM: imx: eliminate macro IOMUX_TO_IRQ()

This patch changes all the static gpio irq number assigning with
IOMUX_TO_IRQ() to run-time assigning with gpio_to_irq call, and
in turn eliminates the macro IOMUX_TO_IRQ().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>