nft: Use ARRAY_SIZE() macro in nft_strerror()

Variable 'table' is an array of type struct table_struct, so this is a
classical use-case for ARRAY_SIZE() macro.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/iptables/nft.c b/iptables/nft.c
index 89b1c7a..3c230c1 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -2888,7 +2888,7 @@
 	    { NULL, ENOENT, "No chain/target/match by that name" },
 	  };
 
-	for (i = 0; i < sizeof(table)/sizeof(struct table_struct); i++) {
+	for (i = 0; i < ARRAY_SIZE(table); i++) {
 		if ((!table[i].fn || table[i].fn == nft_fn)
 		    && table[i].err == err)
 			return table[i].message;