net: Make netconsole src and dest ports configurable

net: Make netconsole src and dest ports configurable

It is desirable to use different port numbers for sending and receiving
packets with netconsole in the case where you have more than one device
on the local subnet with netconsole enabled for broadcast.  When they
use the same port for both, any output from one will look like input to
the other.  This is typlically not desirable.

This patch allows the input and output ports to be specified separately
in the environment.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>