qosmngr: fix lan traffic limited to 1G always

Problem description: Two problems seen,

1. The queues on a port are by default setup to handle maximum rate of 1G
2. The default qos uci config for ipq and brcm platforms is different

Fix:

1. Update queue setup to not impose rate limit, by setting the maximum rate as the maximum rate supported by the port.
2. Update uci default script to generate same config for both platforms