drm/msm/dsi: Adjust probe order

Switch to the documented order dsi-host vs bridge probe.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Caleb Connolly <caleb.connolly@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025151536.1048186-22-maxime@cerno.tech