py/reader: Allow MICROPY_VFS_POSIX to work with MICROPY_READER_POSIX.

py/reader.c

@@ -124,6 +124,8 @@ void mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd) {
     reader->close = mp_reader_posix_close;
 }
 
+#if !MICROPY_VFS_POSIX
+// If MICROPY_VFS_POSIX is defined then this function is provided by the VFS layer
 void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
     int fd = open(filename, O_RDONLY, 0644);
     if (fd < 0) {
@@ -131,5 +133,6 @@ void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
     }
     mp_reader_new_file_from_fd(reader, fd, true);
 }
+#endif
 
 #endif