Set DMA coherent mask to 32-bit which makes PPE offloading engine start working on BPi-R4 which got 4 GiB of RAM. Fixes: 2d75891ebc09 ("net: ethernet: mtk_eth_soc: support 36-bit DMA addressing on MT7988") Suggested-by: Elad Yifee <eladwf@users.github.com> Signed-off-by: Daniel Golle <daniel@makrotopia.org> Link: https://lore.kernel.org/r/97e90925368b405f0974b9b15f1b7377c4a329ad.1706113251.git.daniel@makrotopia.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>