Align with coding style

return statements use parentheses to contain their value.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
diff --git a/scripts/data_files/error.fmt b/scripts/data_files/error.fmt
index e908aac..d106acd 100644
--- a/scripts/data_files/error.fmt
+++ b/scripts/data_files/error.fmt
@@ -62,7 +62,7 @@
             break;
     }
 
-    return NULL;
+    return( NULL );
 }
 
 const char * mbedtls_low_level_strerr( int error_code )
@@ -85,7 +85,7 @@
             break;
     }
 
-    return NULL;
+    return( NULL );
 }
 
 void mbedtls_strerror( int ret, char *buf, size_t buflen )