network/ndisc: sd_ndisc_router_get_{icmp6_ratelimit,retransmission_ti…

…me}() should never fail

This also fixes use of '%m' specifier without passign error code.

src/network/networkd-ndisc.c

@@ -372,10 +372,8 @@ static int ndisc_router_process_icmp6_ratelimit(Link *link, sd_ndisc_router *rt)
                 return 0;
 
         r = sd_ndisc_router_get_icmp6_ratelimit(rt, &icmp6_ratelimit);
-        if (r < 0) {
-                log_link_debug(link, "Failed to get ICMP6 ratelimit from RA, ignoring: %m");
-                return 0;
-        }
+        if (r < 0)
+                return log_link_warning_errno(link, r, "Failed to get ICMP6 ratelimit from RA: %m");
 
         /* We do not allow 0 here. */
         if (!timestamp_is_set(icmp6_ratelimit))
@@ -406,10 +404,8 @@ static int ndisc_router_process_retransmission_time(Link *link, sd_ndisc_router
                 return 0;
 
         r = sd_ndisc_router_get_retransmission_time(rt, &retrans_time);
-        if (r < 0) {
-                log_link_debug_errno(link, r, "Failed to get retransmission time from RA, ignoring: %m");
-                return 0;
-        }
+        if (r < 0)
+                return log_link_warning_errno(link, r, "Failed to get retransmission time from RA: %m");
 
         /* 0 is the unspecified value and must not be set (see RFC4861, 6.3.4) */
         if (!timestamp_is_set(retrans_time))