power button: Wait for charger and battery initialization
power button: Wait for charger and battery initialization

For PWRBTN_STATE_INIT_ON, before attempting to power the
system on, we need to wait for charger and battery to be
ready to supply sufficient power. Check every 100
milliseconds, and give up after 1 second. This allows
time for charger, battery and USB-C PD initialization.

Previously, init-on would fail because it called
set_pwrbtn_to_pch too soon (before charge current had
been initialized, and before the USB-C 3A current was
detected).

BUG=b:72645441,b:74017044
BRANCH=none
TEST=cold reset Grunt with ac/battery connected/disconnected

Change-Id: I0413e7f2d7b19a99c994b51b22f28a2f993137de
Signed-off-by: Edward Hill <db1406b34e091703092b6b136bdfeb2c8125fc0e@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/900049
Reviewed-by: Aaron Durbin <af0622ab041e8b0f8e5819838dcc93898196e71f@chromium.org>
Reviewed-by: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@google.com>

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