Probe ADB miscellaneous devices (ID 7) instead of stopping at ID 6. This

allows us to probe the brightness and volume control buttons on PPC Apple
laptops, though there is not yet a driver to do anything useful with them.

sys/dev/adb/adb_bus.c

@@ -134,7 +134,7 @@ adb_bus_enumerate(void *xdev)
 	/* Enumerate bus */
 	next_free = 8;
 
-	for (i = 1; i < 7; i++) {
+	for (i = 1; i <= 7; i++) {
 	    int8_t first_relocated = -1;
 	    int reply = 0;