ath79: enable UART node for GL-USB150

This was overlooked when adding support for this device.
(It has recently been discovered that this was the only device in
ath79 having &uart disabled.)

Fixes: acc62630132c ("ath79: add support for GL.iNet GL-USB150")

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
(cherry picked from commit 722f1bd549)

target/linux/ath79/dts/ar9331_glinet_gl-usb150.dts

@@ -112,10 +112,6 @@
 	};
 };
 
-&uart {
-	status = "disabled";
-};
-
 &wmac {
 	status = "okay";