net: gmac_rockchip: Add support for RK3576

Signed-off-by: David Wu <david.wu@rock-chips.com>
Change-Id: I762fbc304807ad3e59fac39da37591762578ec1d

rockchip: Add rk3576 Soc support

Change-Id: Ic217b4df45b0b3938dbc54e4156940a1fb42eea0
Signed-off-by: Xuhui Lin <xuhui.lin@rock-chips.com>