NFSv4: Fix brainfart in attribute length calculation

The calculation of the attribute length was 4 bytes off.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Andre Heider <a.heider@gmail.com>
Reported-and-tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index c74d616..3850b01 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1118,11 +1118,11 @@
 				len, ((char *)p - (char *)q) + 4);
 		BUG();
 	}
-	len = (char *)p - (char *)q - (bmval_len << 2);
 	*q++ = htonl(bmval0);
 	*q++ = htonl(bmval1);
 	if (bmval_len == 3)
 		*q++ = htonl(bmval2);
+	len = (char *)p - (char *)(q + 1);
 	*q = htonl(len);
 
 /* out: */