usb: typec: displayport: Move the Configuration VDO helpers to the header

The helpers used for reading and writing the pin assignment
from and to the Configuration VDO will be useful in GPU
drivers, and also UCSI driver after DisplayPort alt mode
support is added to it.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>