Merge branch 'parisc' (PA-RISC compile fixes)

Merge PA-RISC compile fixes from Rolf Eike Beer:
 "Since commit d66acc39 ("bitops: Optimise get_order()") getorder.h
  includes log2.h which leads to an include loop on PA-RISC, bringing a
  bunch of other breakage to light.  This patchset fixes the compilation
  of the current state of 3.4 on HPPA.

  Unchanged against the first version, just added an Ack by Grant."

* emailed from Rolf Eike Beer <eike-kernel@sf-tec.de>: (5 patches)
  parisc: move definition of PAGE0 to asm/page.h
  parisc: add missing include of asm/page.h to asm/pgtable.h
  parisc: drop include of asm/pdc.h from asm/hardware.h
  parisc: add missing forward declarations in asm/hardware.h
  parisc: add missing includes in asm/spinlock.h