net: fec: implement TSO descriptor cleanup

net: fec: implement TSO descriptor cleanup

Implement cleanup of descriptors in the TSO error path of
fec_enet_txq_submit_tso(). The cleanup

- Unmaps DMA buffers for data descriptors skipping TSO header
- Clears all buffer descriptors
- Handles extended descriptors by clearing cbd_esc when enabled

Fixes: 79f339125ea3 ("net: fec: Add software TSO support")
Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20250120085430.99318-1-dheeraj.linuxdev@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>