iMX8DXL: update default hash algorithm for kernel image to SHA256

change default hash algorithm from sha384 to sha256
for computing kernel image hash.

Signed-off-by: Gaurav Jain <gaurav.jain@nxp.com>
(cherry picked from commit e72c588c)

iMX8DXL/soc.mak

@@ -155,7 +155,7 @@ flash_patch: $(MKIMG) $(SECO_FW_NAME) scfw_tcm.bin message_signed.bin
 	./$(MKIMG) -soc DXL -rev A0 -append $(SECO_FW_NAME) -c -scfw scfw_tcm.bin -msg_blk message_signed.bin patch 0x80000000 $(V2X_DUMMY_OCRAM) --out flash.bin
 
 flash_kernel: $(MKIMG) Image imx8dxl-evk.dtb
-	./$(MKIMG) -soc DXL -rev A0 -c -ap Image a35 0x80200000 --data imx8dxl-evk.dtb a35 0x83000000 -out flash.bin
+	./$(MKIMG) -soc DXL -rev A0 -h sha256 -c -ap Image a35 0x80200000 --data imx8dxl-evk.dtb a35 0x83000000 -out flash.bin
 
 parse_container: $(MKIMG) flash.bin
 	./$(MKIMG) -soc DXL -rev A0 -parse flash.bin