Move i.MX8 container image loading support to common/spl

To facilitate testing loading i.MX8 container images, move the
parse-container code to common/spl.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index 6904cf3..a3b44c9 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -79,7 +79,7 @@
 endif
 
 ifeq ($(CONFIG_SPL_BUILD),y)
-obj-$(CONFIG_SPL_LOAD_IMX_CONTAINER) += image-container.o parse-container.o
+obj-$(CONFIG_SPL_LOAD_IMX_CONTAINER) += image-container.o
 endif
 
 ifeq ($(SOC),$(filter $(SOC),imx8ulp imx9))