usb: typec: tcpm: Determine common SVDM Version

usb: typec: tcpm: Determine common 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."

Also clear the fields newly defined in SVDM version 2.0 if the
negotiated SVDM version is 1.0.

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210205033415.3320439-4-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>