Specify signed-ness of constants

We relyed on the default signed-ness of constants, which is usually
signed. This can create MISRA violations, such as:

     bl1/bl1_main.c:257:[MISRA C-2012 10.8 (required)] Cast of composite
     expression off essential type signed to essential type unsigned

These constants were only used as unsigned, so this patch makes them
explicitly unsigned.

Change-Id: I5f1310c881e936077035fbb1d5ffb449b45de3ad
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>

include/bl1/bl1.h

@@ -26,8 +26,8 @@
 /*
  * BL1 SMC version
  */
-#define BL1_SMC_MAJOR_VER		0x0
-#define BL1_SMC_MINOR_VER		0x1
+#define BL1_SMC_MAJOR_VER		UL(0x0)
+#define BL1_SMC_MINOR_VER		UL(0x1)
 
 /*
  * Defines for FWU SMC function ids.