typec: tcpm: Add core support for sink side PPS

This commit adds code to handle requesting of PPS APDOs. Switching
between standard PDOs and APDOs, and re-requesting an APDO to
modify operating voltage/current will be triggered by an
external call into TCPM.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>