[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/contig.c b/arch/ia64/mm/contig.c
index e566ff4..0ee085e 100644
--- a/arch/ia64/mm/contig.c
+++ b/arch/ia64/mm/contig.c
@@ -163,7 +163,7 @@
 	 * get_zeroed_page().
 	 */
 	if (first_time) {
-		void *cpu0_data = __phys_per_cpu_start - PERCPU_PAGE_SIZE;
+		void *cpu0_data = __cpu0_per_cpu;
 
 		first_time=0;