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>
diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 5034147..9a6d818 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -25,6 +25,7 @@
 	depends on ARCH_OMAP2PLUS
 	default y
 	select CPU_V6
+	select MULTI_IRQ_HANDLER
 
 config ARCH_OMAP3
 	bool "TI OMAP3"