tools: add i.MX8/8X image support

i.MX8/8X bootable image type is container type.
The bootable image, containers a container set which supports two
container. The 1st container is for SECO firmware, the 2nd container
needs to include scfw, m4_0/1 image, ACore images per your requirement.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/tools/Makefile b/tools/Makefile
index 0c3341e..3c0521f 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -93,6 +93,7 @@
 			common/image.o \
 			imagetool.o \
 			imximage.o \
+			imx8image.o \
 			kwbimage.o \
 			lib/md5.o \
 			lpc32xximage.o \