Merge branch 'fixes-on-the-open-alliance-tc6-10base-t1x-mac-phy-support-generic-lib'

Parthiban Veerasooran says:

====================
Fixes on the OPEN Alliance TC6 10BASE-T1x MAC-PHY support generic lib

This patch series contain the below fixes.

- Infinite loop error when tx credits becomes 0.
- Race condition between tx skb reference pointers.

v2:
- Added mutex lock to protect tx skb reference handling.

v3:
- Added mutex protection in assigning new tx skb to waiting_tx_skb
  pointer.
- Explained the possible scenario for the race condition with the time
  diagram in the commit message.

v4:
- Replaced mutex with spin_lock_bh() variants as the start_xmit runs in
  BH/softirq context which can't take sleeping locks.
====================

Link: https://patch.msgid.link/20241213123159.439739-1-parthiban.veerasooran@microchip.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>