This starts a large set of alpha patches accumulated since 2.5.18 or
even earlier. All of this was reasonably well tested.
Thanks to Jeff Wiedemeier for SMP testing and fixes.

- sync up with (2.5.18?) pte/pfn/page/tlb etc. macros;
- asm-generic/tlb.h: loading unsigned long constant to unsigned int
  tlb->nr causes compiler warnings on 64 bit platforms.