irqchip/renesas-intc-irqpin: r8a7778 IRLM setup support

Works the same as on r8a7779.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1443607387-19147-1-git-send-email-geert+Brenesas@glider.be


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>