Booting my RK3328-based PINE64 ROCK64 with a debug build of the ATF makes this message visible in the output:
WARNING: BL31: cortex_a53: CPU workaround for 855873 was missing!
Editing plat/rockchip/rk3328/platform.mk to enable this workaround changes the message to
INFO: BL31: cortex_a53: CPU workaround for 855873 was applied
I'll upload a patch that makes this change. (Note this matches the change made in commit dea1e8ee for the RK3399, a related SoC that also includes A53 cores.)