dts: nrf51822: unify /chosen node settings

There's no need for two separate places for this.

Signed-off-by: Martí Bolívar <[email protected]>

Author: mbolivar-nordic

dts/arm/nordic/nrf51822.dtsi

@@ -6,6 +6,7 @@
 / {
 	chosen {
 		zephyr,entropy = &rng;
+		zephyr,flash-controller = &flash_controller;
 	};
 
 	cpus {
@@ -19,10 +20,6 @@
 		};
 	};
 
-	chosen {
-		zephyr,flash-controller = &flash_controller;
-	};
-
 	soc {
 		ficr: ficr@10000000 {
 			compatible = "nordic,nrf-ficr";