ADIN2111 OA mode fixes

[panekmaciej]

• Fix the issue that eth_adin2111_oa_data_read returning error would cause the offload thread to exit and hence RTOS crash, as the offload thread is an essential one. It looks like this was a result of invalid merge or copy paste, the break statements in lines 705 and 711 were meant for internal loop that keeps reading the RX FIFO until is empty. Added the missing loop. Also refactored the code so it is common with OA and non-OA access and the FIFOs are read sequentially port 1 / port 2.
• Fix the issue in eth_adin2111_send_oa_frame with improper EBO calculation. Sending more than 1472 byte packet would cause the frame to exceed maximum Ethernet frame size and cause the packet to be dropped. Without this fix the TCP communication did not work unless TCP send window was lowered with CONFIG_NET_TCP_MAX_SEND_WINDOW_SIZE, but that caused poor TCP performance.

[github-actions]

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[MaureenHelm]

@jpmur can you take a look?

[MaureenHelm]

Needs rebase

[jpmur]

When at the last chunk, you should consider adding ebo to cur instead of cur += ctx->oa_cps; (line 397). This would ensure that the frame length passed to the SPI layer is exactly correct, although I don't think this is a functional issue.

[kartben]

@panekmaciej will you be able to come back to this to address the merge conflicts?

[panekmaciej]

@panekmaciej will you be able to come back to this to address the merge conflicts?

Yes, but after the new year.

[maass-hamburg]

@panekmaciej please also create a issue for this, so this can also be backported