x86_64 clock events conversion - V5

This is a replacement patch series for the patches in -mm.

Functional changes since last version:

- hpet legacy problem solved
- apic calibration reverted to original x8664 code

Otherwise the code is the same as before, but the patches got split up
further. Linus, thanks for the hints.

The series is fully bisectable and hopefully easier to review now.

	tglx

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