arm: dts: Add mac node for rk3308 at dtsi level

The rk3308 only support RMII mode, and if it is output clock
mode, better to use ref_clk pin with drive strength 12ma.

Signed-off-by: David Wu <david.wu@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
1 file changed