Detect whether x2APIC on VMWare is usable without interrupt
redirection support. Older versions of the hypervisor mis-interpret
the cpuid format in ioapic registers when x2APIC is turned on, but IR
is not used by the guest OS.

Based on: Linux commit 4cca6ea04d31c22a7d0436949c072b27bde41f86
Tested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 months