dumpstate: Add USF registry dump.

This collects the output of "usf_reg_edit save -" and adds it to the
bugreport. It is only done on userbuilds for PROTO* and EVT* devices.

Bug: 187081112
Test: Run "adb bugreport <zip>" and verify it contains the output
      from "usf_reg_edit save -".
Change-Id: Ie68b56a3bb211840f33bdb5afbc31b0759641c8e
1 file changed