[IA64] fix bootmem regression on Altix

A recent change prevents SGI Altix from booting.
This patch fixes the problem.

The regresson was introduced in commit 434d53b00d6bb7be0a1d3dcc0d0d5df6c042e164

Signed-off-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

kernel/sched.c

@@ -8128,7 +8128,7 @@ void __init sched_init(void)
 	 * we use alloc_bootmem().
 	 */
 	if (alloc_size) {
-		ptr = (unsigned long)alloc_bootmem_low(alloc_size);
+		ptr = (unsigned long)alloc_bootmem(alloc_size);
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 		init_task_group.se = (struct sched_entity **)ptr;