change: 反正也没支持mkdir/rmdir,干脆注释掉,减少编译警告

luat/vfs/luat_fs_posix.c

@@ -94,10 +94,12 @@ LUAT_WEAK int luat_fs_umount(luat_fs_conf_t *conf) {
 }
 
 int luat_fs_mkdir(char const* _DirName) {
-    return mkdir(_DirName);
+    //return mkdir(_DirName);
+    return -1;
 }
 int luat_fs_rmdir(char const* _DirName) {
-    return rmdir(_DirName);
+    //return rmdir(_DirName);
+    return -1;
 }
 
 #else
@@ -186,10 +188,12 @@ int luat_vfs_posix_umount(void* userdata, luat_fs_conf_t *conf) {
 }
 
 int luat_vfs_posix_mkdir(void* userdata, char const* _DirName) {
-    return mkdir(_DirName);
+    //return mkdir(_DirName);
+    return -1;
 }
 int luat_vfs_posix_rmdir(void* userdata, char const* _DirName) {
-    return rmdir(_DirName);
+    //return rmdir(_DirName);
+    return -1;
 }
 
 #define T(name) .name = luat_vfs_posix_##name