disp: msm: sde: cancel delayed work when in auto-refresh

Display is entering into mode2 since no new frames are queued,
but auto-refresh requires HW to remain active. Make sure to
cancel the timer for entering idle power collapse whenever
there's a kickoff with auto-refresh feature enabled.

Change-Id: I0ac74e514c9893c31506edc3f2d7e069ab9a3ef8
Signed-off-by: Steve Cohen <cohens@codeaurora.org>