arch/parisc/include/asm/pgtable.h: remove unused `old_pte'

parisc's set_pte_at() macro has set-but-not-used variable:

  include/linux/pgtable.h: In function 'pte_clear_not_present_full':
  arch/parisc/include/asm/pgtable.h:96:9: warning: variable 'old_pte' set but not used [-Wunused-but-set-variable]
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/parisc/include/asm/pgtable.h

@@ -93,10 +93,8 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 
 #define set_pte_at(mm, addr, ptep, pteval)			\
 	do {							\
-		pte_t old_pte;					\
 		unsigned long flags;				\
 		spin_lock_irqsave(pgd_spinlock((mm)->pgd), flags);\
-		old_pte = *ptep;				\
 		set_pte(ptep, pteval);				\
 		purge_tlb_entries(mm, addr);			\
 		spin_unlock_irqrestore(pgd_spinlock((mm)->pgd), flags);\