[IA64] silence GCC ia64 unused variable warnings

Tell GCC to stop spewing out unnecessary warnings for unused variables
passed to functions as pointers for ia64 files.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/tlb.c

@@ -175,7 +175,7 @@ EXPORT_SYMBOL(flush_tlb_range);
 void __devinit
 ia64_tlb_init (void)
 {
-	ia64_ptce_info_t ptce_info;
+	ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
 	unsigned long tr_pgbits;
 	long status;