altera intel cyclone v / error: enabling full line of zeros but not enabled in Cortex-A9

[Nico Becker]

hi,
i have an error message booting linux kernel v4.15 with the u-boot 
v2020.01 on an cylcone v with arm core.
the error message is:
L2C-310: enabling full line of zeros but not enabled in Cortex-A9, that 
is not a warning or an message it is an error.

before the update to the version v2020.01, we use the version v2017.09.
i get the following message: L2C-310 full line of zeros enabled for 
Cortex-A9, no error message.

we use our own board with an altera cyclone v, i try severall default 
configs, i got the same error.
it is very hard to find the source code to enable the full line support 
in u-boot.
8.2.3. Write full line of zeros Setting bit [3] of the ACTLR enables 
this feature.
can somebody help me?

thanks a lot