project-lakitu: cos-extensions: add exit failure message for invoking gpu installer on ARM

BUG=b/191050601
TEST=Tryjob and manual invocation of installer on ARM
RELEASE_NOTE=Add error message while invoking gpu installer on ARM.

Change-Id: I57128446b0a39e25c4f773c87574cf94dba89399
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/20150
Reviewed-by: Roy Yang <royyang@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/project-lakitu/app-admin/extensions-manager/extensions-manager-0.0.1-r5.ebuild b/project-lakitu/app-admin/extensions-manager/extensions-manager-0.0.1-r6.ebuild
similarity index 100%
rename from project-lakitu/app-admin/extensions-manager/extensions-manager-0.0.1-r5.ebuild
rename to project-lakitu/app-admin/extensions-manager/extensions-manager-0.0.1-r6.ebuild
diff --git a/project-lakitu/app-admin/extensions-manager/files/cos-extensions.sh b/project-lakitu/app-admin/extensions-manager/files/cos-extensions.sh
index 4c42ca8..60b5163 100755
--- a/project-lakitu/app-admin/extensions-manager/files/cos-extensions.sh
+++ b/project-lakitu/app-admin/extensions-manager/files/cos-extensions.sh
@@ -105,7 +105,17 @@
     esac
 }
 
+check_arch() {
+  arch=$(uname -m)
+  if  [[ ${arch} != "x86_64" ]]; then
+    echo "GPU installation is only supported on X86 for now.
+    Current architecture detected: ${arch}"
+    exit 1
+  fi
+}
+
 run_gpu_installer() {
+  check_arch
   /usr/bin/docker run --rm \
     --name="cos-gpu-installer" \
     --privileged \