netlink: move resolve_ifname() or friends to netlink-util.[ch]

src/resolve/resolvectl.c

@@ -119,7 +119,7 @@ int ifname_mangle(const char *s) {
         if (!iface)
                 return log_oom();
 
-        ifi = resolve_interface(NULL, iface);
+        ifi = rtnl_resolve_interface(NULL, iface);
         if (ifi < 0) {
                 if (ifi == -ENODEV && arg_ifindex_permissive) {
                         log_debug("Interface '%s' not found, but -f specified, ignoring.", iface);
@@ -2018,7 +2018,7 @@ static int verb_status(int argc, char **argv, void *userdata) {
                 STRV_FOREACH(ifname, argv + 1) {
                         int ifindex, q;
 
-                        ifindex = resolve_interface(&rtnl, *ifname);
+                        ifindex = rtnl_resolve_interface(&rtnl, *ifname);
                         if (ifindex < 0) {
                                 log_warning_errno(ifindex, "Failed to resolve interface \"%s\", ignoring: %m", *ifname);
                                 continue;