ppp_generic: fix multilink fragment sizes

Fix bug in multilink fragment size calculation introduced by
commit 9c705260feea6ae329bc6b6d5f6d2ef0227eda0a
"ppp: ppp_mp_explode() redesign"

Signed-off-by: Ben McKeegan <ben@netservers.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index c5f8eb1..1b2c291 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1422,7 +1422,7 @@
 		flen = len;
 		if (nfree > 0) {
 			if (pch->speed == 0) {
-				flen = totlen/nfree;
+				flen = len/nfree;
 				if (nbigger > 0) {
 					flen++;
 					nbigger--;