fix(boards): Define but don't enable uart0.

* Set pro-micro TX/RX pins, but don't enable the UART
  by default.

app/boards/arm/bluemicro840/bluemicro840_v1.dts

@@ -66,12 +66,8 @@
 
 &uart0 {
 	compatible = "nordic,nrf-uarte";
-	status = "okay";
+	tx-pin = <6>;
-	current-speed = <115200>;
+	rx-pin = <8>;
-	tx-pin = <19>;
-	rx-pin = <21>;
-	rts-pin = <23>;
-	cts-pin = <25>;
 };
 
 &usbd {

app/boards/arm/nice_nano/nice_nano.dts

@@ -65,12 +65,8 @@
 
 &uart0 {
 	compatible = "nordic,nrf-uarte";
-	status = "okay";
+	tx-pin = <6>;
-	current-speed = <115200>;
+	rx-pin = <8>;
-	tx-pin = <19>;
-	rx-pin = <21>;
-	rts-pin = <23>;
-	cts-pin = <25>;
 };
 
 &usbd {

app/boards/arm/nrf52840_m2/nrf52840_m2.dts

@@ -51,16 +51,6 @@
 	status = "okay";
 };
 
-&uart0 {
-	compatible = "nordic,nrf-uarte";
-	status = "okay";
-	current-speed = <115200>;
-	tx-pin = <19>;
-	rx-pin = <21>;
-	rts-pin = <23>;
-	cts-pin = <25>;
-};
-
 &usbd {
 	compatible = "nordic,nrf-usbd";
 	status = "okay";

app/boards/arm/nrfmicro/nrfmicro_11.dts

@@ -53,12 +53,8 @@
 
 &uart0 {
 	compatible = "nordic,nrf-uarte";
-	status = "okay";
+	tx-pin = <6>;
-	current-speed = <115200>;
+	rx-pin = <8>;
-	tx-pin = <19>;
-	rx-pin = <21>;
-	rts-pin = <23>;
-	cts-pin = <25>;
 };
 
 &usbd {

app/boards/arm/nrfmicro/nrfmicro_11_flipped.dts

@@ -53,12 +53,8 @@
 
 &uart0 {
 	compatible = "nordic,nrf-uarte";
-	status = "okay";
+	tx-pin = <6>;
-	current-speed = <115200>;
+	rx-pin = <8>;
-	tx-pin = <19>;
-	rx-pin = <21>;
-	rts-pin = <23>;
-	cts-pin = <25>;
 };
 
 &usbd {

app/boards/arm/nrfmicro/nrfmicro_13.dts

@@ -65,12 +65,8 @@
 
 &uart0 {
 	compatible = "nordic,nrf-uarte";
-	status = "okay";
+	tx-pin = <6>;
-	current-speed = <115200>;
+	rx-pin = <8>;
-	tx-pin = <19>;
-	rx-pin = <21>;
-	rts-pin = <23>;
-	cts-pin = <25>;
 };
 
 &usbd {