[IA64] fix arch/ia64/mm/contig.c:235: warning: unused variable `nid'

This warning only shows up with CONFIG_VIRTUAL_MEM_MAP=y and
CONFIG_FLATMEM=y.

There is only one caller left for register_active_ranges() from the
contig.c code ... so it doesn't need to pick up the node number, the
node number is always zero.

Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/init.c

@@ -595,14 +595,9 @@ find_largest_hole (u64 start, u64 end, void *arg)
 }
 
 int __init
-register_active_ranges(u64 start, u64 end, void *nid)
+register_active_ranges(u64 start, u64 end, void *arg)
 {
-	BUG_ON(nid == NULL);
-	BUG_ON(*(unsigned long *)nid >= MAX_NUMNODES);
-
-	add_active_range(*(unsigned long *)nid,
-				__pa(start) >> PAGE_SHIFT,
-				__pa(end) >> PAGE_SHIFT);
+	add_active_range(0, __pa(start) >> PAGE_SHIFT, __pa(end) >> PAGE_SHIFT);
 	return 0;
 }
 #endif /* CONFIG_VIRTUAL_MEM_MAP */