[bldenv]: add march in the multiarch docker build for sonic-slave

Signed-off-by: Guohan Lu <[email protected]>

Author: lguohan

scripts/bldenv/sonic-slave/build.sh

@@ -18,7 +18,7 @@ build_and_push_docker()
     if [ x$arch == x"amd64" ]; then
         SLAVE_BASE_IMAGE=${SLAVE_DIR}
     else
-        SLAVE_BASE_IMAGE=${SLAVE_DIR}-${arch}
+        SLAVE_BASE_IMAGE=${SLAVE_DIR}-march-${arch}
     fi
 
     tmpfile=$(mktemp)