arm: imx: build mach-imx for i.MX8

To enable SPL for i.MX8, we could reuse code in arch/arm/mach-imx.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 8173025..5384981 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -104,7 +104,7 @@
 libs-y += arch/arm/lib/
 
 ifeq ($(CONFIG_SPL_BUILD),y)
-ifneq (,$(CONFIG_MX23)$(CONFIG_MX28)$(CONFIG_MX35)$(filter $(SOC), mx25 mx5 mx6 mx7 mx35 imx8m))
+ifneq (,$(CONFIG_MX23)$(CONFIG_MX28)$(CONFIG_MX35)$(filter $(SOC), mx25 mx5 mx6 mx7 mx35 imx8m imx8))
 libs-y += arch/arm/mach-imx/
 endif
 else