drm/msm/dsi: Remove dsi_phy_write_[un]delay()

These are dummy wrappers that do literally nothing interesting.
Remove them.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/590703/
Link: https://lore.kernel.org/r/20240423-topic-msm_cleanup-v1-2-b30f39f43b90@linaro.org


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