Adding rx/tx offloading to params_supported

This allows rx/tx offloading to pass through to the Salt network
module so that it can be disabled.

network/defaults.yaml

@@ -21,6 +21,8 @@ Debian:
       - post_up_cmds
       - post_down_cmds
       - noifupdown
+      - rx
+      - tx
       {#- bonding #}
       - master
       - mode
@@ -84,6 +86,8 @@ RedHat:
       - post_up_cmds
       - post_down_cmds
       - noifupdown
+      - rx
+      - tx
       {#- bonding #}
       - master
       - mode