drm/msm/dsi: drop global msm_dsi_phy_type enumaration

With the current upstream driver the msm_dsi_phy_type enum does not make
much sense: all DSI PHYs are probed using the dt bindings, the phy type
is not passed between drivers. Use quirks in phy individual PHY drivers
to differentiate minor harware differences and drop the enum.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Tested-by: Stephen Boyd <swboyd@chromium.org> # on sc7180 lazor
Link: https://lore.kernel.org/r/20210331105735.3690009-8-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>