Revert "file: Convert file to a memfile as soon as possible"

This reverts commit a1bcf3c09b.

common/fs/file.s2.c

@@ -106,10 +106,6 @@ void *freadall(struct file_handle *fd, uint32_t type) {
     } else {
         void *ret = ext_mem_alloc_type(fd->size, type);
         fd->read(fd, ret, 0, fd->size);
-        fd->close(fd);
-        fd->is_memfile = true;
-        fd->readall = true;
-        fd->fd = ret;
         return ret;
     }
 }