On a keyboard-less, volume-button-less board, we support simplified
sysrq handling.
For Fizz, we use the recovery button to trigger sysrq event and
holding it down to trigger warm reset.
BUG=b:38418116,b:38417391
BRANCH=none
TEST=On Fizz, try
1. Press recovery button and release -> sysrq sent
2. Press and hold recovery button -> warm reset
3. Press recovery button and power button -> enter recovery mode
Change-Id: If8760319dba3df4545e9805b396ac89c241dae80
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/537817
Reviewed-by: Aaron Durbin <adurbin@chromium.org>