touchpad_st: memory corruption detection
touchpad_st: memory corruption detection

The touchpad firmware will send out a beacon every second. Therefore, if
there is no events (touch event / error event / beacon event) for more
than 3 seconds, we should assume that touchpad hangs, and we should
reset the touchpad.
This requires touchpad FW >= v25.0.

BRANCH=nocturne
BUG=b:113315759
TEST=manual on whiskers
Signed-off-by: Wei-Han Chen <5413a119f383c3f4549c3ef659403f393bf06e9d@chromium.org>

Change-Id: I6dc57705ebb8ef9f9d0ffde3c3243704b7ff88ee
Reviewed-on: https://chromium-review.googlesource.com/1238753
Commit-Ready: Wei-Han Chen <5413a119f383c3f4549c3ef659403f393bf06e9d@chromium.org>
Tested-by: Wei-Han Chen <5413a119f383c3f4549c3ef659403f393bf06e9d@chromium.org>
Reviewed-by: Wei-Han Chen <5413a119f383c3f4549c3ef659403f393bf06e9d@chromium.org>
Reviewed-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec