sh: intc - add support for 7780

This patch converts the cpu specific 7780 setup code to use the
new intc controller. Many new vectors are added and also support for
external interrupt sense configuration. So with this patch it is now
possible to configure external interrupt pins as edge or level
triggered using set_irq_type().

No external interrupts are registered by default.
Use plat_irq_setup_pins() to select between IRQ or IRL mode.

This patch also fixes the Alarm IRQ for the RTC.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>