Staging: hv: cleanup network driver

Minor stuff:
   * Add module description
   * Remove variable set but never used.
   * Move variable inside conditional

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>