clocksource/drivers/imx-sysctr: Remove unused includes

There is nothing in use from of_address.h/of_irq.h, remove them.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1584413713-7376-1-git-send-email-Anson.Huang@nxp.com