tcp: Use BIT() for OPTION_* constants

Extending these flags using the existing (1 << x) pattern triggers
complaints from checkpatch. Instead of ignoring checkpatch modify the
existing values to use BIT(x) style in a separate commit.
Signed-off-by: NLeonard Crestez <cdleonard@gmail.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_output.c

@@ -408,13 +408,13 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)
 	return tp->snd_una != tp->snd_up;
 }
 
-#define OPTION_SACK_ADVERTISE	(1 << 0)
-#define OPTION_TS		(1 << 1)
-#define OPTION_MD5		(1 << 2)
-#define OPTION_WSCALE		(1 << 3)
-#define OPTION_FAST_OPEN_COOKIE	(1 << 8)
-#define OPTION_SMC		(1 << 9)
-#define OPTION_MPTCP		(1 << 10)
+#define OPTION_SACK_ADVERTISE	BIT(0)
+#define OPTION_TS		BIT(1)
+#define OPTION_MD5		BIT(2)
+#define OPTION_WSCALE		BIT(3)
+#define OPTION_FAST_OPEN_COOKIE	BIT(8)
+#define OPTION_SMC		BIT(9)
+#define OPTION_MPTCP		BIT(10)
 
 static void smc_options_write(__be32 *ptr, u16 *options)
 {