usb: typec: Manage SVDM version

usb: typec: Manage SVDM version

PD Spec Revision 3.0 Version 2.0 + ECNs 2020-12-10
  6.4.4.2.3 Structured VDM Version
  "The Structured VDM Version field of the Discover Identity Command
  sent and received during VDM discovery Shall be used to determine the
  lowest common Structured VDM Version supported by the Port Partners or
  Cable Plug and Shall continue to operate using this Specification
  Revision until they are Detached."

Add a variable in typec_capability to specify the highest SVDM version
supported by the port and another variable in typec_partner to cache the
negotiated SVDM version between the port and the partner.

Also add setter/getter functions for the negotiated SVDM version.

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210205033415.3320439-2-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>