octeontx2-pf: ethtool expose qos stats

This patch extends ethtool stats support for QoS send queues as well.
upon the number of transmit channels change request, Ensures the real
number of transmit queues are equal to active QoS send queues plus
configured transmit queues.

    ethtool -S eth0
    txq_qos0: bytes: 3021391800
    txq_qos0: frames: 1998275
    txq_qos1: bytes: 4619766312
    txq_qos1: frames: 3055401
    ...
    ...

Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>