npcx: CEC: Improve pulse-width measurements
npcx: CEC: Improve pulse-width measurements

Take into account the time from the interrupt is triggered until
the timer is set when recharging the timer.

Signed-off-by: Stefan Adolfsson <e50dd6be847b40d13b2945548d6ccde363cae74b@chromium.org>

BUG=b:76467407
BRANCH=none
TEST=Using temprorary debug-prints.
CQ-DEPEND=CL:1030227

Change-Id: Ia36bd73ff5efcff719db7b7915212f30a8e555f3
Reviewed-on: https://chromium-review.googlesource.com/1030228
Commit-Ready: Stefan Adolfsson <e50dd6be847b40d13b2945548d6ccde363cae74b@chromium.org>
Tested-by: Stefan Adolfsson <e50dd6be847b40d13b2945548d6ccde363cae74b@chromium.org>
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>

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