x86: add hpet sanity checks

Some BIOSes advertise HPET at 0x0. We really do no want to
allocate a resource there. Check for it and leave early.

Other BIOSes tell us the HPET is at 0xfed0000000000000
instead of 0xfed00000. Add a check and fix it up with a warning
on user request.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>