Fix MISRA rule 8.4 Part 1

Rule 8.4: A compatible declaration shall be visible when
          an object or function with external linkage is defined

Fixed for:
	make DEBUG=1 PLAT=fvp LOG_LEVEL=50 all

Change-Id: I7c2ad3f5c015411c202605851240d5347e4cc8c7
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/include/bl1/bl1.h b/include/bl1/bl1.h
index 41d436d..dd03de0 100644
--- a/include/bl1/bl1.h
+++ b/include/bl1/bl1.h
@@ -83,6 +83,7 @@
 void bl1_print_next_bl_ep_info(const struct entry_point_info *bl_ep_info);
 
 void bl1_main(void);
+void bl1_plat_prepare_exit(entry_point_info_t *ep_info);
 
 /*
  * Check if the total number of FWU SMC calls are as expected.