Add new variable to set architecture var

Author: MaxBed4d

etc/kayobe/overcloud-dib.yml

@@ -70,6 +70,9 @@ overcloud_dib_git_elements_extra:
     version: "aarch64-image-build"
     elements_path: "elements"
 
+
+overcloud_dib_architecture: "arm64"
+
 # List of git repositories containing Diskimage Builder (DIB) elements. See
 # stackhpc.openstack.os_images role for usage. Default is a combination of
 # overcloud_dib_git_elements_default and overcloud_dib_git_elements_extra.