ARM: dts: imx: Convert i.MX8M flash.bin image generation to binman

Rework the flash.bin image generation such that it uses the new binman
nxp_imx8mimage etype. This way, the flash.bin is assembled in correct
order using plain binman, without any workarounds or sections assembled
in special DT node order.

Reviewed-By: Tim Harvey <tharvey@gateworks.com>
Tested-By: Tim Harvey <tharvey@gateworks.com> # imx8mm_venice
Tested-by: Fabio Estevam <festevam@gmail.com> # imx8mm-evk and imx8mn-evk
Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/arch/arm/dts/imx8mp-dhcom-u-boot.dtsi b/arch/arm/dts/imx8mp-dhcom-u-boot.dtsi
index b05be57..cb37e28 100644
--- a/arch/arm/dts/imx8mp-dhcom-u-boot.dtsi
+++ b/arch/arm/dts/imx8mp-dhcom-u-boot.dtsi
@@ -136,7 +136,7 @@
 };
 
 &binman {
-	itb {
+	section {
 		fit {
 			images {
 				fdt-dto-imx8mp-dhcom-som-overlay-eth1xfast {