staging: typec: tcpm: Check for port type for Try.SRC/Try.SNK

Enable Try.SRC or Try.SNK only when port_type is
DRP. Try.SRC or Try.SNK state machines are not
valid for SRC only or SNK only ports.

Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>