x86: hpet: allow force enable on ICH10 HPET

Intel "Smackover" x58 BIOS don't have HPET enabled in the BIOS, so allow
to force enable it at least.  The register layout is the same as in other
recent ICHs, so all the code can be reused.

Using numerical PCI-ID because it's unlikely the PCI-ID will be used
anywhere else.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>