ARM: tegra: remove clock-frequency properties from serial nodes

Currently, the serial nodes define both a clock-frequency and a clocks
property. We should not provide both, since they might conflict.

In practice, this also causes problems since the of_serial driver uses
the clock-frequency property in preference to the clocks property, and
hence doesn't clk_prepare_enable() the clock, which may then leave it
with no known users, and hence the common clock framework will disable
it, thus breaking the port, which is usually the console.

Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/boot/dts/tegra30.dtsi

@@ -234,7 +234,6 @@
 		reg = <0x70006000 0x40>;
 		reg-shift = <2>;
 		interrupts = <0 36 0x04>;
-		clock-frequency = <408000000>;
 		nvidia,dma-request-selector = <&apbdma 8>;
 		clocks = <&tegra_car 6>;
 		status = "disabled";
@@ -244,7 +243,6 @@
 		compatible = "nvidia,tegra30-uart", "nvidia,tegra20-uart";
 		reg = <0x70006040 0x40>;
 		reg-shift = <2>;
-		clock-frequency = <408000000>;
 		interrupts = <0 37 0x04>;
 		nvidia,dma-request-selector = <&apbdma 9>;
 		clocks = <&tegra_car 160>;
@@ -255,7 +253,6 @@
 		compatible = "nvidia,tegra30-uart", "nvidia,tegra20-uart";
 		reg = <0x70006200 0x100>;
 		reg-shift = <2>;
-		clock-frequency = <408000000>;
 		interrupts = <0 46 0x04>;
 		nvidia,dma-request-selector = <&apbdma 10>;
 		clocks = <&tegra_car 55>;
@@ -266,7 +263,6 @@
 		compatible = "nvidia,tegra30-uart", "nvidia,tegra20-uart";
 		reg = <0x70006300 0x100>;
 		reg-shift = <2>;
-		clock-frequency = <408000000>;
 		interrupts = <0 90 0x04>;
 		nvidia,dma-request-selector = <&apbdma 19>;
 		clocks = <&tegra_car 65>;
@@ -277,7 +273,6 @@
 		compatible = "nvidia,tegra30-uart", "nvidia,tegra20-uart";
 		reg = <0x70006400 0x100>;
 		reg-shift = <2>;
-		clock-frequency = <408000000>;
 		interrupts = <0 91 0x04>;
 		nvidia,dma-request-selector = <&apbdma 20>;
 		clocks = <&tegra_car 66>;