net: snmp: fix the wrong ICMP_MIB_MAX value

__ICMP_MIB_MAX is equal to the total number of icmp mib,
So no need to add 1. This wastes 4/8 bytes memory.

Change it to be same as ICMP6_MIB_MAX, TCP_MIB_MAX, UDP_MIB_MAX.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/snmp.h

@@ -61,8 +61,7 @@ struct ipstats_mib {
 
 /* ICMP */
 #define ICMP_MIB_DUMMY	__ICMP_MIB_MAX
-#define ICMP_MIB_MAX	(__ICMP_MIB_MAX + 1)
-
+#define ICMP_MIB_MAX	__ICMP_MIB_MAX
 struct icmp_mib {
 	unsigned long	mibs[ICMP_MIB_MAX];
 };