usb: typec: ucsi: psy: Fix ucsi_psy_get_current_now in non-PD cases

usb: typec: ucsi: psy: Fix ucsi_psy_get_current_now in non-PD cases

current_now would always return 0 in for non-PD power sources, and the
negotiated current based on the Request RDO in PD mode.

For USB Type-C current or legacy Default USB cases current_now will present
the max value of those modes, as that is the equivalent of the Request RDO
in PD.

Also, current_now will now return 0 when the port is disconnected to match
the same behavior of current_max.

Signed-off-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20251208174918.289394-2-bleung@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>