Fix power_state driver for Nyan based boards

1. Add 3 seconds shutdown delay for nyan_big
2. set warm_reset to be on during cold reset
3. Add overlay for nyan_blaze

BUG=None
TEST=local beaglebone_servo build and command
dut-control power_state:off power_state:on
dut-control power_state:reset

Change-Id: Ib0b46c36f3f6f769361603fb9617c1b3389bfaaa
Reviewed-on: https://chromium-review.googlesource.com/202322
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
6 files changed