parisc: Remove PTE load and fault check from L2_ptep macro

This change removes the PTE load and present check from the L2_ptep
macro.  The load and check for kernel pages is now done in the tlb_lock
macro.  This avoids a double load and check for user pages.  The load
and check for user pages is now done inside the lock so the fault
handler can't be called while the entry is being updated.  This version
uses an ordered store to release the lock when the page table entry
isn't present.  It also corrects the check in the non SMP case.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>