ARM i.MX boards: use CONFIG_MULTI_IRQ_HANDLER

Also, add handle_irq callbacks to machine descriptors.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5ebc5d9..975b5dd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -397,6 +397,7 @@
 	select CLKSRC_MMIO
 	select GENERIC_IRQ_CHIP
 	select HAVE_SCHED_CLOCK
+	select MULTI_IRQ_HANDLER
 	help
 	  Support for Freescale MXC/iMX-based family of processors