Log Message:
Update xentools48 and xenkernel48 to 4.8.2, and apply security patches up
to XSA244. Keep PKGREVISION to 1 to account for the fact that it's
not a stock Xen 4.8.2.

Note that, unlike upstream, pv-linear-pt defaults to true, so that
NetBSD PV guests (including dom0) will continue to boot without changes
to boot.cfg