servo v2: change spi_hold to open-drain and init to off.

spi_hold is defined as a open-drain output so it shouldn't actively
drive 'high' value but instead rely on pull-up from DUT.

BUG=chrome-os-partner:53581
TEST=manual,

  sudo servod -b chell
  boot chell device from S5 successfully

Change-Id: Iff31454ec8a5f42e254be134c8c50ca385d46fdd
Reviewed-on: https://chromium-review.googlesource.com/346770
Commit-Ready: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
1 file changed