hinic: add support to query rq info

add debugfs node for querying rq info, for example:
cat /sys/kernel/debug/hinic/0000:15:00.0/RQs/0x0/rq_hw_pi

Signed-off-by: Luo bin <luobin9@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>