usb: typec: ucsi: register with power_supply class

usb: typec: ucsi: register with power_supply class

With this change the UCSI device will show up in
/sys/class/power_supply/. The following values are exported:
- online
- usb_type
- voltage_min
- voltage_max
- voltage_now
- current_max
- current_now

Once a PD-capable type-C power source is connected to the system, GET_PDOS
UCSI command is used to query all source capabilities. Request data object
(RDO) is used to get current values.

Signed-off-by: K V, Abhilash <abhilash.k.v@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200423132058.6972-7-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>