[LLC]: Fix compiler warnings introduced by TX window scaling changes.

Noticed by Olaf Hering.

The comparisons want a u8 here (the data type on the left-hand branch
is a u8 structure member, and the constant on the right-hand branch is
"~((u8) 128)"), but C turns it into an integer so we get:

net/llc/llc_c_ac.c: In function `llc_conn_ac_inc_npta_value':
net/llc/llc_c_ac.c:998: warning: comparison is always true due to limited range of data type
net/llc/llc_c_ac.c:999: warning: large integer implicitly truncated to unsigned type

Fix this up by explicitly recasting the right-hand branch constant
into a "u8" once more.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/llc/llc_c_ac.c

@@ -995,8 +995,8 @@ static int llc_conn_ac_inc_npta_value(struct sock *sk, struct sk_buff *skb)
 		llc->dec_step = 0;
 		llc->dec_cntr = llc->inc_cntr = 2;
 		++llc->npta;
-		if (llc->npta > ~LLC_2_SEQ_NBR_MODULO)
-			llc->npta = ~LLC_2_SEQ_NBR_MODULO ;
+		if (llc->npta > (u8) ~LLC_2_SEQ_NBR_MODULO)
+			llc->npta = (u8) ~LLC_2_SEQ_NBR_MODULO;
 	} else
 		--llc->inc_cntr;
 	return 0;
@@ -1086,8 +1086,8 @@ int llc_conn_ac_inc_tx_win_size(struct sock *sk, struct sk_buff *skb)
 	struct llc_sock *llc = llc_sk(sk);
 
 	llc->k += 1;
-	if (llc->k > ~LLC_2_SEQ_NBR_MODULO)
-		llc->k = ~LLC_2_SEQ_NBR_MODULO ;
+	if (llc->k > (u8) ~LLC_2_SEQ_NBR_MODULO)
+		llc->k = (u8) ~LLC_2_SEQ_NBR_MODULO;
 	return 0;
 }