wireaddr: moves wireaddr_arr_contains to wireaddr.h

...So it can be reused somewhere else

Changelog-None

common/wireaddr.c

@@ -899,3 +899,12 @@ int wireaddr_cmp_type(const struct wireaddr *a,
 		return tal_bytelen(a_wire) - tal_bytelen(b_wire);
 	return cmp;
 }
+
+bool wireaddr_arr_contains(const struct wireaddr *was,
+			   const struct wireaddr *wa)
+{
+	for (size_t i = 0; i < tal_count(was); i++)
+		if (wireaddr_eq(&was[i], wa))
+			return true;
+	return false;
+}

common/wireaddr.h

@@ -197,4 +197,7 @@ struct wireaddr *fromwire_wireaddr_array(const tal_t *ctx, const u8 *ser);
 int wireaddr_cmp_type(const struct wireaddr *a,
 		      const struct wireaddr *b, void *unused);
 
+bool wireaddr_arr_contains(const struct wireaddr *was,
+			   const struct wireaddr *wa);
+
 #endif /* LIGHTNING_COMMON_WIREADDR_H */

gossipd/gossip_generation.c

@@ -20,15 +20,6 @@
 #include <hsmd/hsmd_wiregen.h>
 #include <wire/wire_sync.h>
 
-static bool wireaddr_arr_contains(const struct wireaddr *was,
-				  const struct wireaddr *wa)
-{
-	for (size_t i = 0; i < tal_count(was); i++)
-		if (wireaddr_eq(&was[i], wa))
-			return true;
-	return false;
-}
-
 /* Create a node_announcement with the given signature. It may be NULL in the
  * case we need to create a provisional announcement for the HSM to sign.
  * This is called twice: once with the dummy signature to get it signed and a