Make BL31's ns_entry_info a single-cpu area

ns_entry_info used to be a per-cpu array.  This is a waste of space
because it is only accessed by the primary CPU on the cold boot path.
This patch reduces ns_entry_info to a single-cpu area.

Change-Id: I647c70c4e76069560f1aaad37a1d5910f56fba4c
diff --git a/include/bl31.h b/include/bl31.h
index acb1229..5320e58 100644
--- a/include/bl31.h
+++ b/include/bl31.h
@@ -43,7 +43,7 @@
  ******************************************************************************/
 extern void bl31_platform_setup(void);
 extern meminfo *bl31_plat_sec_mem_layout(void);
-extern el_change_info* bl31_get_next_image_info(unsigned long);
+extern el_change_info* bl31_get_next_image_info(void);
 extern void gic_cpuif_deactivate(unsigned int);
 extern void gic_cpuif_setup(unsigned int);
 extern void gic_pcpu_distif_setup(unsigned int);