ipvs: Remove unused macros

They are not used since commit e4ff67513096 ("ipvs: add
sync_maxlen parameter for the sync daemon")

Signed-off-by: YueHaibing <[e-mail]>
Acked-by: Simon Horman <[e-mail]>
Signed-off-by: Pablo Neira Ayuso <[e-mail]>

net/netfilter/ipvs/ip_vs_sync.c

···
       |                    IPVS Sync Connection (1)                   |
 */
 
-#define SYNC_MESG_HEADER_LEN	4
-#define MAX_CONNS_PER_SYNCBUFF	255 /* nr_conns in ip_vs_sync_mesg is 8 bit */
-
 /* Version 0 header */
 struct ip_vs_sync_mesg_v0 {
 	__u8                    nr_conns;