drivers/ec/ps8751: Perform lazy evaluation of device status

Do not check the status of device during registration. Instead perform a
lazy evaluation of device status when the registered device is accessed.

BUG=chromium:896451
BUG=b:112306866
BRANCH=None
TEST=bootup to ChromeOS by connecting and disconnecting the USB
daughterboard

Change-Id: Iaae538ad0f59020a41be24349b8caf8b9f7d92f0
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1289778
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>
4 files changed