net: Fix tcp_build_and_update_options comment in struct tcp_sock

Noticed this comment didn't get updated when
tcp_build_and_update_options was refactored.

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

include/linux/tcp.h

@@ -406,7 +406,7 @@ struct tcp_sock {
 
 	struct sk_buff_head	out_of_order_queue; /* Out of order segments go here */
 
-	/* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */
+	/* SACKs data, these 2 need to be together (see tcp_options_write) */
 	struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
 	struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/