tools: fix memory leakage issue in acrnlog.c

In function mk_dir(), handler 'dir' returned
 by opendir() is not released before function
 return and results in memory leakage.

Tracked-On: #7098
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>

misc/debug_tools/acrn_log/acrnlog.c

@@ -414,6 +414,7 @@ static int mk_dir(const char *path)
 			} else
 				remove(acrnlog_file);
 		}
+		closedir(dir);
 	}
 
 	return 0;