(wr-nic) step_mode: Step mode patch for remote control added

Step_mode patch adds new command for wrpc CLI and it prevents that gui/stat command
is updated periodically by wrpc monitor. Statistics are collected each time the command is
executed.

Usage:
	step_mode on/off
(wr-nic) ep_filter: Re-directing Etherbone traffic

This patch modifies filter rules in order to re-direct Etherbone traffic corretly.
Packets are inspected (destination port/magic number) in order to decide if they
must be delivered to wrpc, etherbone or nic core.