ARM: omap2plus: convert to CONFIG_MULTI_IRQ_HANDLER

Convert the omap2plus platforms to be using CONFIG_MULTI_IRQ_HANDLER.
Each machine is modified to provide either omap2_intc_handle_irq(),
omap3_intc_handle_irq() or gic_handle_irq().

This allows for a major cleanup, removing the MULTI_OMAP setup
from the interrupt path.

Tested on both Panda and IGEPv2 (single kernel image)

Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/mach-omap2/board-devkit8000.c

@@ -660,6 +660,7 @@ MACHINE_START(DEVKIT8000, "OMAP3 Devkit8000")
 	.map_io		= omap3_map_io,
 	.init_early	= omap35xx_init_early,
 	.init_irq	= omap3_init_irq,
+	.handle_irq	= omap3_intc_handle_irq,
 	.init_machine	= devkit8000_init,
 	.timer		= &omap3_secure_timer,
 MACHINE_END