mctp: Add MCTP package recipe

This change adds a recipe for the libmctp sources, which provide a
library implementing the MCTP base protocol, plus a demulitplexer daemon
to provide a socket-based interface for client applications.

This is covered in the mctp design document:

  https://github.com/openbmc/docs/blob/master/designs/mctp.md

Change-Id: I892e420e50cb8eacbdd27779db3d0edcefbf0fbb
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/recipes-phosphor/mctp/files/default b/recipes-phosphor/mctp/files/default
new file mode 100644
index 0000000..cb33e8b
--- /dev/null
+++ b/recipes-phosphor/mctp/files/default
@@ -0,0 +1 @@
+DEMUX_BINDING_OPTS=null