ARM: mmp: support sparse irq

Add sparse IRQ support in ARCH_MMP.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 95ad5f9..6cae277 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -510,6 +510,7 @@
 	select GENERIC_CLOCKEVENTS
 	select TICK_ONESHOT
 	select PLAT_PXA
+	select SPARSE_IRQ
 	help
 	  Support for Marvell's PXA168/PXA910(MMP) and MMP2 processor line.