fuse: Initialize total_len in fuse_retrieve()

fs/fuse/dev.c:1357: warning: ‘total_len’ may be used uninitialized in this
function

Initialize total_len to zero, else its value will be undefined.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Miklos Szeredi <[e-mail]>

fs/fuse/dev.c

···
 	loff_t file_size;
 	unsigned int num;
 	unsigned int offset;
-	size_t total_len;
+	size_t total_len = 0;
 
 	req = fuse_get_req(fc);
 	if (IS_ERR(req))