disp: msm: sde: ignore HW recovery disable event

The current SDE driver logic during MDP hang cases is to send a capture
event to user-mode if recovery custom event is registered. Otherwise, it
will enforce a device panic for debugging purpose. This might have a race
condition during the display tear-down sequence as user-mode unregisters
the recovery event when the last frame is in progress. If the last frame
causes any MDP hang, it will result in a device reset. Support only the
event registration to avoid this case, since HW recovery is not expected
to be changed dynamically.

Change-Id: I8a11e1060b239ac6827f1d078e3e396cff4c1325
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>