msm: mdss: handle blank while mode switch in progress

When display is getting blanked while mode switch in progress, we
cannot have additional kickoff trigger for cleanup as the state hasn't
been properly transitioned. Instead we can clear the state and destroy
control path to start clean on next update.

Change-Id: I34af01550d79e0d7d465f2c7f873508c296160dd
[veeras@codeaurora.org: Resolved conflicts in mdss_mdp_overlay.c]
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>