arm64: dts: qcom: msm8996: don't use underscore in node name

We have underscore (_) in node name leading to warning:

arch/arm64/boot/dts/qcom/apq8096-db820c.dt.yaml: clocks: $nodename:0: 'clocks' does not match '^([a-z][a-z0-9\\-]+-bus|bus|soc|axi|ahb|apb)(@[0-9a-f]+)?$'
arch/arm64/boot/dts/qcom/apq8096-db820c.dt.yaml: clocks: xo_board: {'type': 'object'} is not allowed for {'compatible': ['fixed-clock'], '#clock-cells': [[0]], 'clock-frequency': [[19200000]], 'clock-output-names': ['xo_board'], 'phandle': [[115]]}

Fix this by changing node name to use dash (-)

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210308060826.3074234-10-vkoul@kernel.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

arch/arm64/boot/dts/qcom/msm8996.dtsi

@@ -19,14 +19,14 @@
 	chosen { };
 
 	clocks {
-		xo_board: xo_board {
+		xo_board: xo-board {
 			compatible = "fixed-clock";
 			#clock-cells = <0>;
 			clock-frequency = <19200000>;
 			clock-output-names = "xo_board";
 		};
 
-		sleep_clk: sleep_clk {
+		sleep_clk: sleep-clk {
 			compatible = "fixed-clock";
 			#clock-cells = <0>;
 			clock-frequency = <32764>;