usb: typec: tcpm: Disregard vbus off while in PR_SWAP_SNK_SRC_SOURCE_ON

usb: typec: tcpm: Disregard vbus off while in PR_SWAP_SNK_SRC_SOURCE_ON

During PR_SWAP sequence, when TCPM is waiting in PR_SWAP_SNK_SRC_SOURCE_ON
for the vbus source to ramp up, TCPM would prematurely exit
PR_SWAP_SNK_SRC_SOURCE_ON and transition to SNK_UNATTACHED state when a
vbus off notification is received. This should not be the case as vbus
can still be off while in PR_SWAP_SNK_SRC_SOURCE_ON and the vbus source
has PD_T_NEWSRC to ramp up.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20201125020703.1604979-1-badhri@google.com
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>