mufs: expose struct mufs_dir internally

source/fs/mufs/dir.c

@@ -13,12 +13,6 @@
 #include "path.h"
 #include "tree.h"
 
-struct mufs_dir {
-	struct mufs *fs;
-	struct mufs_tree *tree;
-	uint32_t va;
-};
-
 char *mufs_abspath(const char *path)
 {
 	char *s, *p, *next, *prev;

source/fs/mufs/dir.h

@@ -1,5 +1,11 @@
 #pragma once
 
+struct mufs_dir {
+	struct mufs *fs;
+	struct mufs_tree *tree;
+	uint32_t va;
+};
+
 struct mufs_dtree {
 	uint32_t file_size;
 	uint32_t root;