drm/msm/dpu: move widebus logic to its own API

Widebus enablement is decided by the interfaces based on their specific
checks and that already happens with DSI/DP specific helpers. Let's
invoke these helpers from dpu_encoder_is_widebus_enabled() to make it
cleaner overall.

Signed-off-by: Paloma Arellano <quic_parellan@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/579632/
Link: https://lore.kernel.org/r/20240222194025.25329-10-quic_parellan@quicinc.com


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