ETCD need to add UNSUPPORT environment in AArch64

Closes-bug: #1708575

Change-Id: I77e78389ac7b8df9ba9f84b072f446d2e03d84d1
Signed-off-by: Kevin Zhao <kevin.zhao@arm.com>
diff --git a/lib/etcd3 b/lib/etcd3
index 0e1fbd5..bc24790 100644
--- a/lib/etcd3
+++ b/lib/etcd3
@@ -57,6 +57,9 @@
     iniset -sudo $unitfile "Service" "Type" "notify"
     iniset -sudo $unitfile "Service" "Restart" "on-failure"
     iniset -sudo $unitfile "Service" "LimitNOFILE" "65536"
+    if is_arch "aarch64"; then
+        iniset -sudo $unitfile "Service" "Environment" "ETCD_UNSUPPORTED_ARCH=arm64"
+    fi
 
     $SYSTEMCTL daemon-reload
     $SYSTEMCTL enable $ETCD_SYSTEMD_SERVICE