imx8ulp_evk: enable binman support

Enable binman support and add documentation for the
imx8ul-evk board.

Signed-off-by: Gary Bisson <bisson.gary@gmail.com>
diff --git a/arch/arm/dts/imx8ulp-evk-u-boot.dtsi b/arch/arm/dts/imx8ulp-evk-u-boot.dtsi
index 608bde3..f67fe16 100644
--- a/arch/arm/dts/imx8ulp-evk-u-boot.dtsi
+++ b/arch/arm/dts/imx8ulp-evk-u-boot.dtsi
@@ -3,6 +3,8 @@
  * Copyright 2021 NXP
  */
 
+#include "imx8ulp-u-boot.dtsi"
+
 / {
 	mu@27020000 {
 		compatible = "fsl,imx8ulp-mu";