drm/msm/dp: Rely on hpd_enable/disable callbacks

drm/msm/dp: Rely on hpd_enable/disable callbacks

The DisplayPort controller's internal HPD interrupt handling is used for
cases where the HPD signal is connected to a GPIO which is pinmuxed into
the DisplayPort controller. In other configurations the HPD notification
might be delivered by the DRM framework from an associated bridge.

This difference is not appropriately represented by the "is_edp"
boolean, but is properly represented by the frameworks invocation of the
hpd_enable() and hpd_disable() callbacks. Switch the current condition
to rely on these callbacks instead.

This ensures appropriate handling of the three cases; no bridge
connected, a bridge without DRM_BRIDGE_OP_HPD and a bridge with
DRM_BRIDGE_OP_HPD.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/514414/
Link: https://lore.kernel.org/r/20221207220012.16529-9-quic_bjorande@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>