Increase extpower task stack size due to occasional stack
overflow in extpower task on plugging/unpluggin AC.
BUG=chrome-os-partner:36760
BRANCH=samus
TEST=load onto samus, connect/disconnect a bunch of times
and check high water mark on stack usage: 368/512
Change-Id: I4531176ce6f15356a2267cdecf907a7694567da9
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/249920
Reviewed-by: Shawn N <shawnn@chromium.org>