Minimal-printf: Fix wrapping of vsnprintf for ARM compiler

Substituting vsnprintf and vprintf instead of __2vsnprintf and __2vprintf
respectively allows calls to vsnprintf and vprintf
to be substituted with the minimal-printf variants for the ARM toolchain.

Author: hugueskamba

platform/source/minimal-printf/mbed_printf_armlink_overrides.c

@@ -66,17 +66,12 @@ int $Sub$$__2snprintf(char *buffer, size_t length, const char *format, ...)
     return result;
 }
 
-int $Sub$$__2vprintf(char *buffer, const char *format, ...)
+int $Sub$$vprintf(const char *format, va_list arguments)
 {
-    va_list arguments;
-    va_start(arguments, format);
-    int result = mbed_minimal_formatted_string(buffer, LONG_MAX, format, arguments, stdout);
-    va_end(arguments);
-
-    return result;
+    return mbed_minimal_formatted_string(NULL, LONG_MAX, format, arguments, stdout);
 }
 
-int $Sub$$__2vsnprintf(char *buffer, size_t length, const char *format, va_list arguments)
+int $Sub$$vsnprintf(char *buffer, size_t length, const char *format, va_list arguments)
 {
     return mbed_minimal_formatted_string(buffer, length, format, arguments, NULL);
 }