net: mana: Enable debugfs files for MANA device

Implement debugfs in MANA driver to be able to view RX,TX,EQ queue
specific attributes and dump their gdma queues.
These dumps can be used by other userspace utilities to improve
debuggability and troubleshooting

Following files are added in debugfs:

/sys/kernel/debug/mana/
|-------------- 1
    |--------------- EQs
    |                 |------- eq0
    |                 |          |---head
    |                 |          |---tail
    |                 |          |---eq_dump
    |                 |------- eq1
    |                 .
    |                 .
    |
    |--------------- adapter-MTU
    |--------------- vport0
                      |------- RX-0
                      |          |---cq_budget
                      |          |---cq_dump
                      |          |---cq_head
                      |          |---cq_tail
                      |          |---rq_head
                      |          |---rq_nbuf
                      |          |---rq_tail
                      |          |---rxq_dump
                      |------- RX-1
                      .
                      .
                      |------- TX-0
                      |          |---cq_budget
                      |          |---cq_dump
                      |          |---cq_head
                      |          |---cq_tail
                      |          |---sq_head
                      |          |---sq_pend_skb_qlen
                      |          |---sq_tail
                      |          |---txq_dump
                      |------- TX-1
                      .
                      .

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>