ia64: Rename init_thread_union to init_task_mem to avoid conflicting

	declration in <linux/sched.h>.

arch/ia64/kernel/head.S

@@ -144,13 +144,13 @@ start_ap:
 	movl r3=task_for_booting_cpu
  	;;
 	ld8 r3=[r3]
-	movl r2=init_thread_union
+	movl r2=init_task
 	;;
 	cmp.eq isBP,isAP=r3,r0
 	;;
 (isAP)	mov r2=r3
 #else
-	movl r2=init_thread_union
+	movl r2=init_task
 	cmp.eq isBP,isAP=r0,r0
 #endif
 	;;

arch/ia64/kernel/init_task.c

@@ -26,17 +26,17 @@ struct mm_struct init_mm = INIT_MM(init_mm);
  * We need to make sure that this is properly aligned due to the way process stacks are
  * handled. This is done by having a special ".data.init_task" section...
  */
-#define init_thread_info	init_thread_union.s.thread_info
+#define init_thread_info	init_task_mem.s.thread_info
 
-union init_thread {
+static union {
 	struct {
 		struct task_struct task;
 		struct thread_info thread_info;
 	} s;
 	unsigned long stack[KERNEL_STACK_SIZE/sizeof (unsigned long)];
-} init_thread_union __attribute__((section(".data.init_task"))) = {{
-	.task =		INIT_TASK(init_thread_union.s.task),
-	.thread_info =	INIT_THREAD_INFO(init_thread_union.s.task)
+} init_task_mem __attribute__((section(".data.init_task"))) = {{
+	.task =		INIT_TASK(init_task_mem.s.task),
+	.thread_info =	INIT_THREAD_INFO(init_task_mem.s.task)
 }};
 
-asm (".global init_task; init_task = init_thread_union");
+asm (".global init_task; init_task = init_task_mem");