Add Sha to arm64 host image environment

This adds the same Sha that is generated in the
manifest to the host image.  This should be an
exact match such that the same host image should
produce a matching manifest that is then skipped
during DFU.

Bug: 145029114
Test: local build, boot, and DFU attempt
Change-Id: I155cbc8af599362338b9f2a50625aba6684c7fc5
diff --git a/tools/create_base_image_arm.sh b/tools/create_base_image_arm.sh
index 71a3168..b65600c 100755
--- a/tools/create_base_image_arm.sh
+++ b/tools/create_base_image_arm.sh
@@ -142,6 +142,8 @@
 find_script=if test -e mmc ${devnum}:${distro_bootpart} /boot/boot.scr; then echo Found U-Boot script /boot/boot.scr; run run_scr; fi
 run_scr=load mmc ${devnum}:${distro_bootpart} ${scriptaddr} /boot/boot.scr; source ${scriptaddr}
 EOF
+	script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+	echo "Sha=`${script_dir}/gen_sha.sh --kernel ${KERNEL_DIR}`" >> ${tmpfile}
 	${ANDROID_HOST_OUT}/bin/mkenvimage -s 32768 -o ${bootenv} - < ${tmpfile}
 fi