usb: typec: intel_pmc_mux: Check the port status before connect

The PMC microcontroller that we use for configuration, does
not supply any status information back. For port status we
need to talk to another controller on the board called IOM
(I/O manager).

By checking the port status before configuring the muxes, we
can make sure that we do not reconfigure the port after
bootup when the system firmware (for example BIOS) has
already configured it.

Using the status information also to check if DisplayPort
HPD is still asserted when the cable plug is disconnected,
and clearing it if it is.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Rajmohan Mani <rajmohan.mani@intel.com>
Reviewed-by: Utkarsh Patel <utkarsh.h.patel@intel.com>
Tested-by: Utkarsh Patel <utkarsh.h.patel@intel.com>
Link: https://lore.kernel.org/r/20200907142428.35838-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>