arm64: dts: rockchip: improve rk3328-roc-cc rgmii performance.

Currently the rk3328-roc-cc ethernet is enabled using "snps,force_thresh_dma_mode".
While this works, the performance leaves a lot to be desired.
A previous attempt to improve performance used "snps,txpbl = <0x4>".
This also allowed networking to function, but performance varied between boards.

This patch takes that one step further.
Set txpbl and rxpbl to 0x4.
This can also be accomplished with "snps,pbl =<0x4>" which affects both.
Also set "snps,aal" which forces address aligned DMA mode.

Fixes: 4bc4d601

 (arm64: dts: rockchip: fix rk3328-roc-cc gmac2io stability issues)
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Leonidas P. Papadakos <papadakospan@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>