This reverts commit 2c87c6f9fbddc5b84d67b2fa3f432fcac6d99d93.
Meanwhile it turned out that the following commit is the proper
workaround for the issue that 2c87c6f9fbdd tries to address. a3a57bf07de2 ("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.