arm64: dts: rockchip: add dma-coherent for pcie and gmac of RK3576

arm64: dts: rockchip: add dma-coherent for pcie and gmac of RK3576

The RK3576 SoC employs ARM CCI for maintaining cache coherency
between the CPU cluster and high-speed peripherals including USB3,
SATA, GMAC, and PCIe controllers. While the USB3 and SATA controllers
were correctly marked as dma-coherent, the GMAC and PCIe nodes were
overlooked.

Without dma-coherent, the kernel falls back to software cache maintenance
for DMA operations, requiring explicit cache flushing and invalidating.
This adds significant overhead that degrades performance in high-throughput
workloads.

Add the missing dma-coherent properties to enable hardware coherency and
avoid unnecessary software cache management overhead.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Link: https://patch.msgid.link/1764313762-78063-1-git-send-email-shawn.lin@rock-chips.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>