ipvs: use explicitly signed chars

The `char` type with no explicit sign is sometimes signed and sometimes
unsigned. This code will break on platforms such as arm, where char is
unsigned. So mark it here as explicitly signed, so that the
todrop_counter decrement and subsequent comparison is correct.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/ipvs/ip_vs_conn.c

@@ -1265,8 +1265,8 @@ static inline int todrop_entry(struct ip_vs_conn *cp)
 	 * The drop rate array needs tuning for real environments.
 	 * Called from timer bh only => no locking
 	 */
-	static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
-	static char todrop_counter[9] = {0};
+	static const signed char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
+	static signed char todrop_counter[9] = {0};
 	int i;
 
 	/* if the conn entry hasn't lasted for 60 seconds, don't drop it.