disp: msm: sde: cancel delayed_off_work before reinitialization

Canceling delayed_off_work in encoder pre_modeset might not be
executed in all cases, but the following encoder enable might
initialize the work.

This will lead to list corruption as delayed_off work list node
is reinitialized before removing from linked list.
Move canceling delayed_off_work to start of encoder mode_set to
ensure work is canceled before reinitialization.

Change-Id: I38687604f2eedced308ea02019c162022725534e
Signed-off-by: Lei Chen <quic_chenlei@quicinc.com>
Signed-off-by: Jayaprakash Madisetty <quic_jmadiset@quicinc.com>