[IA64] Put the space for cpu0 per-cpu area into .data section

Initial fix for making sure that we can access percpu variables
in all C code (commit: 10617bbe84628eb18ab5f723d3ba35005adde143)
inadvertantly allocated the memory in the "percpu" section of
the vmlinux ELF executable.  This confused kexec/dump.

Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index 78026aa..d8c5fcd 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -144,7 +144,7 @@
 
 	for_each_possible_early_cpu(cpu) {
 		if (cpu == 0) {
-			void *cpu0_data = __phys_per_cpu_start - PERCPU_PAGE_SIZE;
+			void *cpu0_data = __cpu0_per_cpu;
 			__per_cpu_offset[cpu] = (char*)cpu0_data -
 				__per_cpu_start;
 		} else if (node == node_cpuid[cpu].nid) {