usb: typec: mux: intel_pmc_mux: Fix DP alternate mode entry

usb: typec: mux: intel_pmc_mux: Fix DP alternate mode entry

commit 130206a88683d859f63ed6d4a56ab5c2b4930c8e upstream.

The PMC needs to be notified separately about HPD (hotplug
detected) signal being high after mode entry. There is a bit
"HPD High" in the Alternate Mode Request that the driver
already sets, but that bit is only valid when the
DisplayPort Alternate Mode is directly entered from
disconnected state.

Fixes: 5c4edcdbcd97 ("usb: typec: mux: intel: Fix DP_HPD_LVL bit field")
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Tested-by: Prashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20200529131753.15587-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>