sd-networkd: rename link_get_state to link_get_setup_state

Suggested by Kay and Lennart.

src/libsystemd/sd-network/sd-network.c

@@ -92,7 +92,7 @@ _public_ int sd_network_get_ntp(char ***ret) {
         return network_get_strv("NTP", ret);
 }
 
-_public_ int sd_network_link_get_state(int ifindex, char **state) {
+_public_ int sd_network_link_get_setup_state(int ifindex, char **state) {
         _cleanup_free_ char *s = NULL, *p = NULL;
         int r;