On VBUS event, only wake PD task if task_start() has already
been called.
BUG=none
BRANCH=samus
TEST=make buildall. use similar patch on ryu and sysjump
back and forth while toggling vbus and make sure we don't
crash.
Change-Id: I79152cd2325949dea080d432d80600ff62d37085
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/242231
Reviewed-by: Vic Yang <victoryang@chromium.org>