dts: bindings: i2s: replace underscore with hyphen

replace underscore with hyphen as per device tree specification

Signed-off-by: Jilay Pandya <[email protected]>

Author: jilaypandya

dts/bindings/i2s/litex,i2s.yaml

@@ -13,6 +13,6 @@ properties:
   reg:
     required: true
 
-  fifo_depth:
+  fifo-depth:
     type: int
     required: true

dts/riscv/riscv32-litex-vexriscv.dtsi

@@ -298,7 +298,7 @@
 				"rx_stat",
 				"rx_conf",
 				"fifo";
-			fifo_depth = <256>;
+			fifo-depth = <256>;
 			status = "disabled";
 		};
 		i2s_tx: i2s_tx@e000b000 {
@@ -321,7 +321,7 @@
 				"tx_stat",
 				"tx_conf",
 				"fifo";
-			fifo_depth = <256>;
+			fifo-depth = <256>;
 			status = "disabled";
 		};
 		clock-outputs {