sys/x86/xen/hvm.c:
	Set cpu_ops correctly for Xen hypervisors lacking the
	vector callback feature.

	Set preliminary Xen cpu_ops settings during early HVM
	initialization.  The old location raced with the startup
	of APs.

Submitted by:	Roger Pau Monné
Reviewed by:	gibbs
Approved by:	re (blanket Xen)
Remove duplicate entry for the host(1) man page.

Approved by:	re (blanket)