RDMA/bnxt_re: Avoid resource leak in case the NQ registration fails

In case the NQ alloc/enable fails, free up the already allocated/enabled
NQ before reporting failure. Also, track the alloc/enable using proper
state checking.

Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>