Fix MISRA rule 8.8 in common code

Rule 8.8: The static storage class specifier shall be used
          in all declarations of objects and functions that
          have internal linkage.

Change-Id: I1e94371caaadebb2cec38d0ae0fa5c59e43369e0
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

bl1/bl1_main.c

@@ -163,7 +163,7 @@ void bl1_main(void)
  * TODO: Add support for alternative image load mechanism e.g using virtio/elf
  * loader etc.
  ******************************************************************************/
-void bl1_load_bl2(void)
+static void bl1_load_bl2(void)
 {
 	image_desc_t *image_desc;
 	image_info_t *image_info;