ARM: dts: uniphier: add interrupts to support card serial

Since commit e69f5dc623f9 ("dt-bindings: serial: Convert 8250 to
json-schema"), the schema for "ns16550a" is checked.

Since then, 'make ARCH=arm dtbs_check' is so noisy because the
required property 'interrupts' is missing.

Signed-off-by: Masahiro Yamada <[e-mail]>

arch/arm/boot/dts/uniphier-ld4-ref.dts

···
 	interrupts = <1 8>;
 };
 
+&serialsc {
+	interrupts = <1 8>;
+};
+
 &serial0 {
 	status = "okay";
 };

arch/arm/boot/dts/uniphier-ld6b-ref.dts

···
 	interrupts = <4 8>;
 };
 
+&serialsc {
+	interrupts = <4 8>;
+};
+
 &serial0 {
 	status = "okay";
 };

arch/arm/boot/dts/uniphier-pro4-ref.dts

···
 	interrupts = <2 8>;
 };
 
+&serialsc {
+	interrupts = <2 8>;
+};
+
 &serial0 {
 	status = "okay";
 };

arch/arm/boot/dts/uniphier-sld8-ref.dts

···
 	interrupts = <0 8>;
 };
 
+&serialsc {
+	interrupts = <0 8>;
+};
+
 &serial0 {
 	status = "okay";
 };