mips: bmips: add ar-5315 usb support

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

arch/mips/dts/comtrend,ar-5315u.dts

@@ -21,6 +21,10 @@
 	};
 };
 
+&ehci {
+	status = "okay";
+};
+
 &leds {
 	status = "okay";
 
@@ -67,6 +71,10 @@
 	};
 };
 
+&ohci {
+	status = "okay";
+};
+
 &spi {
 	status = "okay";
 
@@ -83,3 +91,7 @@
 	u-boot,dm-pre-reloc;
 	status = "okay";
 };
+
+&usbh {
+	status = "okay";
+};