net: arc_emac: make the rockchip emac document more compatible

Add the rk3036 SoCs to match driver for document since the emac driver
has supported the rk3036 SoCs.

This patch adds the rk3036/rk3066/rk3188 SoCS to compatible for rockchip
emac ducument. Also, that will suit for other SoCs in the future.
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexander Kochetkov <al.kochet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/emac_rockchip.txt

-* ARC EMAC 10/100 Ethernet platform driver for Rockchip Rk3066/RK3188 SoCs
+* ARC EMAC 10/100 Ethernet platform driver for Rockchip RK3036/RK3066/RK3188 SoCs
 
 Required properties:
-- compatible: Should be "rockchip,rk3066-emac" or "rockchip,rk3188-emac"
-  according to the target SoC.
+- compatible: should be "rockchip,<name>-emac"
+   "rockchip,rk3036-emac": found on RK3036 SoCs
+   "rockchip,rk3066-emac": found on RK3066 SoCs
+   "rockchip,rk3188-emac": found on RK3188 SoCs
 - reg: Address and length of the register set for the device
 - interrupts: Should contain the EMAC interrupts
 - rockchip,grf: phandle to the syscon grf used to control speed and mode