Some subnet managers expect the GetResponse from a SetPortInfo MAD to
contain the new link state.  The transition is not immediate, so we
often end up returning the previous link state.  This can cause the SM
to fail to activate the port.

Fix by waiting for up to 20us for the link state transition to take
effect.

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

These cards very nearly support our current IB Verbs model.  There is
one minor difference: multicast packets will always be delivered by
the hardware to QP0, so the driver has to redirect them to the
appropriate QP.  This means that QP owners may see receive completions
for buffers that they never posted.  Nothing in our current codebase
will break because of this.