greybus: svc: add flags and traffic class parameter to connection create op

The AP needs to be able to specify L4 CPort flags and traffic class
parameters on a connection-by-connection basis. Extend the connection
create operation to accept these. Since there's no policy to decide
these, fix them at TC0 with end-to-end-flow control, controlled segment
dropping, and CPort safety valve enabled.

Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Perry Hung <perry@leaflabs.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>