VPP-279: Document changes for vnet/vnet/devices

Add doxygen documentation for netmap CLI commands.

Change-Id: I8d3ce12b1cfa5af30ddcd31cb476ca4652cfc2f3
Signed-off-by: Billy McFall <bmcfall@redhat.com>
diff --git a/src/vnet/devices/af_packet/cli.c b/src/vnet/devices/af_packet/cli.c
index 5c55cb4..6baa26e 100644
--- a/src/vnet/devices/af_packet/cli.c
+++ b/src/vnet/devices/af_packet/cli.c
@@ -96,6 +96,11 @@
  * is the name of the specified veth pair. Use the
  * '<em>show interfaces</em>' command to display host interface details.
  *
+ * This command has the following optional parameters:
+ *
+ * - <b>hw-addr <mac-addr></b> - Optional ethernet address, can be in either
+ * X:X:X:X:X:X unix or X.X.X cisco format.
+ *
  * @cliexpar
  * Example of how to create a host interface tied to one side of an
  * existing linux veth pair named vpp1: