Capitalise MPS trace macros

Capitalise the MPS trace macros, as per the coding style (and make a slight
change to naming convention to avoid a name collision).

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/mps_trace.c b/library/mps_trace.c
index dc0577d..6026a07 100644
--- a/library/mps_trace.c
+++ b/library/mps_trace.c
@@ -102,19 +102,19 @@
 
     switch( ty )
     {
-        case mbedtls_mps_trace_comment:
+        case MBEDTLS_MPS_TRACE_TYPE_COMMENT:
             mbedtls_printf( "@ " );
             break;
 
-        case mbedtls_mps_trace_call:
+        case MBEDTLS_MPS_TRACE_TYPE_CALL:
             mbedtls_printf( "+--> " );
             break;
 
-        case mbedtls_mps_trace_error:
+        case MBEDTLS_MPS_TRACE_TYPE_ERROR:
             mbedtls_printf( "E " );
             break;
 
-        case mbedtls_mps_trace_return:
+        case MBEDTLS_MPS_TRACE_TYPE_RETURN:
             mbedtls_printf( "< " );
             break;