ppp: use for_each_set_bit_from

Use for_each_set_bit_from to iterate over all the set bit in a memory
region.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Kozlov <xeb@mail.ru>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ppp/pptp.c

@@ -116,8 +116,8 @@ static int lookup_chan_dst(u16 call_id, __be32 d_addr)
 	int i;
 
 	rcu_read_lock();
-	for (i = find_next_bit(callid_bitmap, MAX_CALLID, 1); i < MAX_CALLID;
-	     i = find_next_bit(callid_bitmap, MAX_CALLID, i + 1)) {
+	i = 1;
+	for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
 		sock = rcu_dereference(callid_sock[i]);
 		if (!sock)
 			continue;