net/bnxt: create aggregation rings when needed

net/bnxt: create aggregation rings when needed

Aggregation rings are needed when PMD needs to support jumbo frames, LRO.
Currently we are creating the aggregation rings whether jumbo frames or
LRO has been enabled or disabled. This causes unnecessary allocation of
mbufs needing larger mbuf pool which is not used at all.

This patch modifies the code to create aggregation rings only when
needed.

Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Lance Richardson <lance.richardson@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>