ARM: tegra: Fix SLINK compatible string on Tegra30

The SLINK controller found on Tegra30 is not compatible with its
predecessor found on Tegra20. Drop the fallback compatible string.
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra30.dtsi

@@ -666,7 +666,7 @@ i2c@7000d000 {
 	};
 
 	spi@7000d400 {
-		compatible = "nvidia,tegra30-slink", "nvidia,tegra20-slink";
+		compatible = "nvidia,tegra30-slink";
 		reg = <0x7000d400 0x200>;
 		interrupts = <GIC_SPI 59 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;
@@ -680,7 +680,7 @@ spi@7000d400 {
 	};
 
 	spi@7000d600 {
-		compatible = "nvidia,tegra30-slink", "nvidia,tegra20-slink";
+		compatible = "nvidia,tegra30-slink";
 		reg = <0x7000d600 0x200>;
 		interrupts = <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;
@@ -694,7 +694,7 @@ spi@7000d600 {
 	};
 
 	spi@7000d800 {
-		compatible = "nvidia,tegra30-slink", "nvidia,tegra20-slink";
+		compatible = "nvidia,tegra30-slink";
 		reg = <0x7000d800 0x200>;
 		interrupts = <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;
@@ -708,7 +708,7 @@ spi@7000d800 {
 	};
 
 	spi@7000da00 {
-		compatible = "nvidia,tegra30-slink", "nvidia,tegra20-slink";
+		compatible = "nvidia,tegra30-slink";
 		reg = <0x7000da00 0x200>;
 		interrupts = <GIC_SPI 93 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;
@@ -722,7 +722,7 @@ spi@7000da00 {
 	};
 
 	spi@7000dc00 {
-		compatible = "nvidia,tegra30-slink", "nvidia,tegra20-slink";
+		compatible = "nvidia,tegra30-slink";
 		reg = <0x7000dc00 0x200>;
 		interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;
@@ -736,7 +736,7 @@ spi@7000dc00 {
 	};
 
 	spi@7000de00 {
-		compatible = "nvidia,tegra30-slink", "nvidia,tegra20-slink";
+		compatible = "nvidia,tegra30-slink";
 		reg = <0x7000de00 0x200>;
 		interrupts = <GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;