queue_api: add subqueue variant netif_subqueue_sent

queue_api: add subqueue variant netif_subqueue_sent

Add a new function, netif_subqueue_sent, which is a wrapper for
netdev_tx_sent_queue.

Drivers that use the subqueue variant macros, netif_subqueue_xxx,
identify queue by index and are not required to obtain
struct netdev_queue explicitly.

Such drivers still need to call netdev_tx_sent_queue which is a
counterpart of netif_subqueue_completed_wake. Allowing drivers to use a
subqueue variant for this purpose improves their code consistency by
always referring to queue by its index.

Signed-off-by: Gur Stavi <gur.stavi@huawei.com>
Link: https://patch.msgid.link/909a5c92db49cad39f0954d6cb86775e6480ef4c.1749038081.git.gur.stavi@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>