drm/msm/dsi: Allow to specify dsi config as pdata

Config autodetect based on DSI controller version is quite limited
since several qcom SoCs can integrate a DSI controller with the same
version, but with different config (io_offset, supplies, etc).

This change allows to specify dsi config via device data pointer.
config autodetect is still used in case data pointer is NULL.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/474089/
Link: https://lore.kernel.org/r/1644853060-12222-1-git-send-email-loic.poulain@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>