Importing new xen API headers (RELEASE-4.11.1)

["Cherry G. Mathew" <cherry%NetBSD.org@localhost>]

Hello,

I've imported xen headers from tag RELEASE-4.11.1 into 
sys/external/mit/xen-include-public/dist/

I haven't switched over the sources yet, but in order to do this, I need
to bump the compiled API version __XEN_INTERFACE_VERSION__ to 0x00030201
because this is the lowest source API version that this release
supports.

I have a patch that does this already for our existing kernels, but for
dom0 I need to disable ixg(4) until a bug in the driver os dependant
compile path is sorted out. I will discuss the issue in the commit
disabling the driver for dom0s.

This is just a warning for those running -current that if you depend on
ixg(4), it's going to stop working for now until the rototil is done.

Many Thanks,

-- 
~cherry