[ros-kernel] LPC implementation

[Ge van Geldorp]

While doing some small work on LPC ports, I noticed a race condition
which occurs if both the client and the server simultaneously close
their port. This can cause the OtherPort member to be to NULL but still
be referenced, causing a BSOD. I've been thinking about a way to fix
this, but haven't come up with a clean, simple way to do it. I can see
two solutions: 1) introduce a global lock (not clean) or 2) use one big
port object for both sides of the connection instead of the 2 objects we
have now (not simple).

I'm not going to pursue this any further at this point, if anyone else
wants to have a go at it please do. Problem is registered in Bugzilla as
#418 http://www.reactos.com/bugzilla/show_bug.cgi?id=418

Gé van Geldorp.