etherswitch: Add minimal support for mv88e6170 switch

sys/dev/etherswitch/e6000sw/e6000sw.c

@@ -302,6 +302,10 @@ e6000sw_probe(device_t dev)
 		description = "Marvell 88E6352";
 		sc->num_ports = 7;
 		break;
+	case MV88E6171:
+		description = "Marvell 88E6171";
+		sc->num_ports = 7;
+		break;
 	case MV88E6172:
 		description = "Marvell 88E6172";
 		sc->num_ports = 7;

sys/dev/etherswitch/e6000sw/e6000swreg.h

@@ -45,6 +45,7 @@ struct atu_opt {
 #define	MV88E6341	0x3410
 #define	MV88E6352	0x3520
 #define	MV88E6172	0x1720
+#define	MV88E6171	0x1710
 #define	MV88E6176	0x1760
 #define	MV88E6190	0x1900
 #define	MV88E6190X	0x0a00