clocksource : Nomadik-mtu : fix missing irq initialization

This patch fix the clock device irq field which is not initialized.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: patches@linaro.org
Cc: linus.walleij@stericsson.com
Cc: john.stultz@linaro.org
Link: http://lkml.kernel.org/r/1361547870-32638-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>