ARM: OMAP: Work around hardcoded interrupts

Commit 9a1091ef ("irqchip: gic: Support hierarchy irq domain")
changed the GIC driver to use a non-legacy IRQ domain on DT
platforms. This patch assumes that DT-driven systems are getting
all of their interrupts from device tree.

Turns out that OMAP has quite a few hidden gems, and still uses
hardcoded interrupts despite having fairly complete DTs.

This patch attempts to work around these by offering a translation
method that can be called directly from the hwmod code, if present.
The same hack is sprinkled over PRCM and TWL.

It isn't pretty, but it seems to do the job without having to add
more hacks to the interrupt controller code.

Tested on OMAP4 (Panda-ES) and OMAP5 (UEVM5432).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Nishanth Menon <nm@ti.com>
[tony@atomide.com: updated to fix make randconfig issue]
Signed-off-by: Tony Lindgren <tony@atomide.com>