Pull in latest fixes from dtc, up to 0060471

This includes a small battery of /memreserve/ fixes to make sure dtc is
properly writing these regions into the output file and reading them back
out.

As of this update, dtc will now also assume common defaults for -I/-O if
only one is specified; namely, dts for one implies dtb for the other and
vice versa (Requested by: jhibbits, preserves GPL dtc behavior too).

MFC after: 1 week