net: airoha: Introduce ndo_select_queue callback

Airoha EN7581 SoC supports 32 Tx DMA rings used to feed packets to QoS
channels. Each channels supports 8 QoS queues where the user can apply
QoS scheduling policies. In a similar way, the user can configure hw
rate shaping for each QoS channel.
Introduce ndo_select_queue callback in order to select the tx queue
based on QoS channel and QoS queue. In particular, for dsa device select
QoS channel according to the dsa user port index, rely on port id
otherwise. Select QoS queue based on the skb priority.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>