ifconfig: add carriage return when printing transceiver

[Denis Fondras]

When transceiver is unknown (among others), a carriage return is missing.

Before :
[root@er6p:~] ifconfig cnmac0 sff                               
cnmac0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
        lladdr 18:e8:29:b6:d4:a9
        index 1 priority 0 llprio 3
        media: Ethernet autoselect (none)
        status: no carrier
        transceiver: Unknown [root@er6p:~] 

After :
[root@er6p:/usr/src/sbin/ifconfig] ifconfig cnmac0 sff     
cnmac0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
        lladdr 18:e8:29:b6:d4:a9
        index 1 priority 0 llprio 3
        media: Ethernet autoselect (none)
        status: no carrier
        transceiver: Unknown 
[root@er6p:/usr/src/sbin/ifconfig]


Index: sff.c
===================================================================
RCS file: /cvs/src/sbin/ifconfig/sff.c,v
retrieving revision 1.11
diff -u -p -r1.11 sff.c
--- sff.c       16 Apr 2019 09:32:06 -0000      1.11
+++ sff.c       26 Apr 2019 09:36:01 -0000
@@ -361,6 +361,9 @@ if_sff_info(int s, const char *ifname, i
        case SFF8024_ID_QSFP28:
                error = if_sff8636(s, ifname, dump, &pg0);
                break;
+       default:
+               putchar('\n');
+               break;
        }
 
        return (error);