kmod-sched-cake: diffserv3 & change defaults

Follow upstream cake:

diffserv3: a simple 3 tin classifier more in line with sqm-scripts
defaults for other qdisc algorithms.

defaults: default qdisc options are now diffserv3 and triple-isolate.

Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>