Fix MISRA Rule 5.3 Part 2

Use a _ prefix for Macro arguments to prevent that argument from
hiding variables of the same name in the outer scope

Rule 5.3: An identifier declared in an inner scope shall not
          hide an identifier declared in an outer scope

Fixed For:
    make LOG_LEVEL=50 PLAT=fvp

Change-Id: I67b6b05cbad4aeca65ce52981b4679b340604708
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/common/tf_printf.c b/common/tf_printf.c
index d403983..9d8333a 100644
--- a/common/tf_printf.c
+++ b/common/tf_printf.c
@@ -15,13 +15,13 @@
  * The tf_printf implementation for all BL stages
  ***********************************************************/
 
-#define get_num_va_args(args, lcount) \
-	(((lcount) > 1) ? va_arg(args, long long int) :	\
-	((lcount) ? va_arg(args, long int) : va_arg(args, int)))
+#define get_num_va_args(_args, _lcount) \
+	(((_lcount) > 1) ? va_arg(_args, long long int) :	\
+	((_lcount) ? va_arg(_args, long int) : va_arg(_args, int)))
 
-#define get_unum_va_args(args, lcount) \
-	(((lcount) > 1) ? va_arg(args, unsigned long long int) :	\
-	((lcount) ? va_arg(args, unsigned long int) : va_arg(args, unsigned int)))
+#define get_unum_va_args(_args, _lcount) \
+	(((_lcount) > 1) ? va_arg(_args, unsigned long long int) :	\
+	((_lcount) ? va_arg(_args, unsigned long int) : va_arg(_args, unsigned int)))
 
 void tf_string_print(const char *str)
 {