ARM: mxs: Add build configuration for mxs

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index b87aed0..485cad1 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -158,6 +158,7 @@
 machine-$(CONFIG_ARCH_MX3)		:= mx3
 machine-$(CONFIG_ARCH_MX5)		:= mx5
 machine-$(CONFIG_ARCH_MXC91231)		:= mxc91231
+machine-$(CONFIG_ARCH_MXS)		:= mxs
 machine-$(CONFIG_ARCH_NETX)		:= netx
 machine-$(CONFIG_ARCH_NOMADIK)		:= nomadik
 machine-$(CONFIG_ARCH_NS9XXX)		:= ns9xxx