spi: rockchip: add compatible string for rv1108 spi

The spi on rv1108 is the same as other rockchip based
socs, add compatible string for it.
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/spi-rockchip.txt

@@ -6,6 +6,7 @@ and display controllers using the SPI communication interface.
 Required Properties:
 
 - compatible: should be one of the following.
+    "rockchip,rv1108-spi" for rv1108 SoCs.
     "rockchip,rk3036-spi" for rk3036 SoCS.
     "rockchip,rk3066-spi" for rk3066 SoCs.
     "rockchip,rk3188-spi" for rk3188 SoCs.

drivers/spi/spi-rockchip.c

@@ -914,6 +914,7 @@ static const struct dev_pm_ops rockchip_spi_pm = {
 };
 
 static const struct of_device_id rockchip_spi_dt_match[] = {
+	{ .compatible = "rockchip,rv1108-spi", },
 	{ .compatible = "rockchip,rk3036-spi", },
 	{ .compatible = "rockchip,rk3066-spi", },
 	{ .compatible = "rockchip,rk3188-spi", },