i2c: imx: remove unneeded mach/irqs.h inclusion

Remove unneeded mach/irq.h inclusion from i2c-imx driver.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: linux-i2c@vger.kernel.org
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>