xen: balloon: use correct type for frame_list

This is now a xen_pfn_t.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/balloon.c

@@ -87,7 +87,7 @@ struct balloon_stats balloon_stats;
 EXPORT_SYMBOL_GPL(balloon_stats);
 
 /* We increase/decrease in batches which fit in a page */
-static unsigned long frame_list[PAGE_SIZE / sizeof(unsigned long)];
+static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)];
 
 #ifdef CONFIG_HIGHMEM
 #define inc_totalhigh_pages() (totalhigh_pages++)