FROMLIST: usb: typec: tcpci: Add support to report vSafe0V

This change adds vbus_vsafe0v which when set, makes TCPM
query for VSAFE0V by assigning the tcpc.is_vbus_vsafe0v callback.
Also enables ALERT.ExtendedStatus which is triggered when
status of EXTENDED_STATUS.vSafe0V changes.
EXTENDED_STATUS.vSafe0V is set when vbus is at vSafe0V and
cleared otherwise.

Bug: 173747861
Link: https://lore.kernel.org/linux-usb/20201202040840.663578-2-badhri@google.com/T/#u


Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Change-Id: I970d0be609b80cb2ae934d09cbbf6cc480e67294