powerpc/4xx: Have Warp take advantage of GPIO LEDs default-state = keep

The GPIO LEDS driver now has a default state of "keep".  Update the Warp DTS
and platform file to take advantage of this new state.  This removes the
hardcoding of the two LEDs on the Warp.

Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
diff --git a/arch/powerpc/boot/dts/warp.dts b/arch/powerpc/boot/dts/warp.dts
index 01bfb56..31605ee 100644
--- a/arch/powerpc/boot/dts/warp.dts
+++ b/arch/powerpc/boot/dts/warp.dts
@@ -261,10 +261,11 @@
 				compatible = "gpio-leds";
 				green {
 					gpios = <&GPIO1 0 0>;
-					default-state = "on";
+					default-state = "keep";
 				};
 				red {
 					gpios = <&GPIO1 1 0>;
+					default-state = "keep";
 				};
 			};