icmp: move icmp_err_convert[] to .rodata

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/icmp.h

@@ -28,7 +28,7 @@ struct icmp_err {
   unsigned	fatal:1;
 };
 
-extern struct icmp_err icmp_err_convert[];
+extern const struct icmp_err icmp_err_convert[];
 #define ICMP_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.icmp_statistics, field)
 #define ICMP_INC_STATS_BH(net, field)	SNMP_INC_STATS_BH((net)->mib.icmp_statistics, field)
 #define ICMPMSGOUT_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.icmpmsg_statistics, field+256)

net/ipv4/icmp.c

@@ -114,7 +114,7 @@ struct icmp_bxm {
 /* An array of errno for error messages from dest unreach. */
 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
 
-struct icmp_err icmp_err_convert[] = {
+const struct icmp_err icmp_err_convert[] = {
 	{
 		.errno = ENETUNREACH,	/* ICMP_NET_UNREACH */
 		.fatal = 0,