drm/msm/dpu: move PINGPONG_NONE check to dpu_lm_init()

Move the check for lm->pingpong being not NONE from dpu_rm_init() to
dpu_lm_init(), following the change to dpu_hw_intf_init().

Suggested-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/538206/
Link: https://lore.kernel.org/r/20230519234025.2864377-5-dmitry.baryshkov@linaro.org


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