extmod/vfs_lfs: Fix littlefs bindings to build in nan-box mode.

Signed-off-by: Damien George <damien@micropython.org>

extmod/vfs_lfsx.c

@@ -442,7 +442,7 @@ STATIC mp_import_stat_t MP_VFS_LFSx(import_stat)(void *self_in, const char *path
     MP_OBJ_VFS_LFSx *self = self_in;
     struct LFSx_API (info) info;
     mp_obj_str_t path_obj = { { &mp_type_str }, 0, 0, (const byte *)path };
-    path = MP_VFS_LFSx(make_path)(self, &path_obj);
+    path = MP_VFS_LFSx(make_path)(self, MP_OBJ_FROM_PTR(&path_obj));
     int ret = LFSx_API(stat)(&self->lfs, path, &info);
     if (ret == 0) {
         if (info.type == LFSx_MACRO(_TYPE_REG)) {