Make deviceSelector.hardwareAddr in config.yaml case-insensitive (#1414)

* fix(docs): mention case sensitivity for talos_nic

* fix: make deviceSelector.hardwareAddr case-insensitive

bootstrap/templates/kubernetes/bootstrap/talos/talconfig.yaml.j2

@@ -41,7 +41,7 @@ nodes:
     controlPlane: #{ (item.controller) | string | lower }#
     networkInterfaces:
       - deviceSelector:
-          hardwareAddr: "#{ item.talos_nic }#"
+          hardwareAddr: "#{ item.talos_nic | lower }#"
         dhcp: false
         #% if bootstrap_talos.vlan %#
         vlans: