Add missing dependency on the AUX bus implementation.

Fixes: c3bf8e21 ("drm/msm/dp: Add eDP support via aux_bus")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/483406/
Link: https://lore.kernel.org/r/20220426004128.2832555-1-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>