board: sl28: remove u-boot from loadable DT node

It is not needed. Remove it.

Signed-off-by: Michael Walle <michael@walle.cc>
diff --git a/arch/arm/dts/fsl-ls1028a-kontron-sl28-u-boot.dtsi b/arch/arm/dts/fsl-ls1028a-kontron-sl28-u-boot.dtsi
index 2375549..87e14d6 100644
--- a/arch/arm/dts/fsl-ls1028a-kontron-sl28-u-boot.dtsi
+++ b/arch/arm/dts/fsl-ls1028a-kontron-sl28-u-boot.dtsi
@@ -80,21 +80,18 @@
 				conf-1 {
 					description = "fsl-ls1028a-kontron-sl28";
 					firmware = "uboot";
-					loadables = "uboot";
 					fdt = "fdt-1";
 				};
 
 				conf-2 {
 					description = "fsl-ls1028a-kontron-sl28-var3";
 					firmware = "uboot";
-					loadables = "uboot";
 					fdt = "fdt-2";
 				};
 
 				conf-3 {
 					description = "fsl-ls1028a-kontron-sl28-var4";
 					firmware = "uboot";
-					loadables = "uboot";
 					fdt = "fdt-3";
 				};
 			};