Add HPET emulation to qemu (Beth Kon)

This patch adds HPET emulation.  It can be disabled with -disable-hpet.  An hpet
provides a more finely granular clocksource than otherwise available on PC.
This means that latency-dependent applications (e.g. multimedia) will generally
be smoother when using the HPET.

Signed-off-by: Beth Kon <eak@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6081 c046a42c-6fe2-441c-8c8c-71466251a162