arm/imx6q: add smp and cpu hotplug support

It adds smp and cpu hotplug support for imx6q.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 40372a8..66b8648 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -611,6 +611,7 @@
 	select ARM_GIC
 	select CACHE_L2X0
 	select CPU_V7
+	select HAVE_ARM_SCU
 	select HAVE_IMX_GPC
 	select HAVE_IMX_MMDC
 	select HAVE_IMX_SRC