This reverts commit 07f4bb1696d068163f564c9763d2714d44b553a3.
Meanwhile it turned out that the following commit is the proper
workaround for the issue that 07f4bb1696d0 tries to address. 74daaf75f404 ("net: stmmac: work around sporadic tx issue on link-up")
It's nor clear why the to be reverted commit helped for one user,
for others it didn't make a difference.