ath79: Fix GL-AR300M USB trigger

Correct a typo preventing USB trigger to work on AR300M.

Signed-off-by: Robert Marko <[email protected]>

target/linux/ath79/dts/qca9533_glinet_ar300m.dtsi

@@ -77,7 +77,7 @@
 
 	hub_port: port@1 {
 		reg = <1>;
-		#trigger-soruce-cells = <0>;
+		#trigger-source-cells = <0>;
 	};
 };