usb: typec: tcpm: Fix up PR_SWAP when vsafe0v is signalled

usb: typec: tcpm: Fix up PR_SWAP when vsafe0v is signalled

During PR_SWAP, When TCPM is in PR_SWAP_SNK_SRC_SINK_OFF, vbus is
expected to reach VSAFE0V when source turns off vbus. Do not move
to SNK_UNATTACHED state when this happens.

Fixes: 28b43d3d746b ("usb: typec: tcpm: Introduce vsafe0v for vbus")
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20210517192112.40934-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>