net: tn40xx: add basic Tx handling

net: tn40xx: add basic Tx handling

This patch adds device specific structures to initialize the hardware
with basic Tx handling. The original driver loads the embedded
firmware in the header file. This driver is implemented to use the
firmware APIs.

The Tx logic uses three major data structures; two ring buffers with
NIC and one database. One ring buffer is used to send information
about packets to be sent for NIC. The other is used to get information
from NIC about packet that are sent. The database is used to keep the
information about DMA mapping. After a packet is sent, the db is used
to free the resource used for the packet.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://patch.msgid.link/20240623235507.108147-5-fujita.tomonori@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>