Disable the auto negotiation if the port is set to fixed-link.

Tested on SG-3100 (ARMADA38X) and Espresso.bin (A37x0).  Fixes the network
on espresso.bin.

Sponsored by:	Rubicon Communications, LLC (Netgate)

sys/dev/neta/if_mvneta.c

@@ -757,6 +757,7 @@ mvneta_attach(device_t self)
 
 	} else {
 		/* Fixed-link, use predefined values */
+		mvneta_update_autoneg(sc, FALSE);
 		ifmedia_init(&sc->mvneta_ifmedia, 0, mvneta_mediachange,
 		    mvneta_mediastatus);