net/bnxt: fix Rx performance by removing spinlock

net/bnxt: fix Rx performance by removing spinlock

The spinlock was trying to protect scenarios where rx_queue stop/start
could be initiated dynamically. Assigning bnxt_dummy_recv_pkts and
bnxt_dummy_xmit_pkts immediately to avoid concurrent access of mbuf in Rx
and cleanup path should help achieve the same result.

Fixes: 14255b351537 ("net/bnxt: fix queue start/stop operations")
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Rahul Gupta <rahul.gupta@broadcom.com>