drm/msm/disp/dpu: use atomic enable/disable callbacks for encoder functions

Use atomic variants for encoder callback functions such that
certain states like self-refresh can be accessed as part of
enable/disable sequence.

Signed-off-by: Kalyan Thota <quic_kalyant@quicinc.com>
Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/524738/
Link: https://lore.kernel.org/r/1677774797-31063-12-git-send-email-quic_vpolimer@quicinc.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>