Add HPET cputimer.
HPET - High Precision Event Timers. Only main counter is used
currently. This cputimer should be faster than ACPI-fast24 and
ACPI-safe, so give it highest priority.
HPET is not enabled by default. You could add "hpet" to
debug.acpi.enabled to enable it.
Obtained-from: FreeBSD
Submitted-by: Dmitry Komissaroff <aunoor@gmail.com> w/ mod from me
Local change:
Try mapping 0x100 bytes HPET register space, if broken ACPI tables
are encountered (like one of my testing box); 0x100 is large enough
to cover the main counter.