tools/netconsole: Add support for socat

socat is a very powerful tool to work with socets (and not only)
in UNIX systems. Let's add support for it in netconsole.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>