clean up device tree package

flake.nix

@@ -10,7 +10,6 @@
       pkgs = import nixpkgs { system = "x86_64-linux"; };
       not-os-cfg = not-os-configured.config.system;
       fsbl-support = ./fast-servo/fsbl-support;
-      dts-support = ./fast-servo/dts-support;
 
       patched-not-os = pkgs.applyPatches {
         name = "not-os-patched";
@@ -214,7 +213,9 @@
           dontFixup = true;
         };
 
-        u-boot = (pkgs.pkgsCross.armv7l-hf-multiplatform.buildUBoot {
+        u-boot = let
+          fast-servo-dts = fast-servo/fast-servo.dts;
+          in (pkgs.pkgsCross.armv7l-hf-multiplatform.buildUBoot {
             defconfig = "xilinx_zynq_virt_defconfig";
             patches = [] ++ pkgs.lib.optional (board == "fast-servo") ./fast-servo/u-boot.patch;
             preConfigure = ''
@@ -237,7 +238,7 @@
             filesToInstall = [ "u-boot.elf" ];
           }).overrideAttrs (oldAttrs: {
             postUnpack = ''
-            cp ${dts-support}/fast-servo.dts $sourceRoot/arch/arm/dts/zynq-fast-servo.dts
+              cp ${fast-servo-dts} $sourceRoot/arch/arm/dts/zynq-fast-servo.dts
             '';
             postInstall = ''
               mkdir -p $out/dts
@@ -274,8 +275,6 @@
           }
           ''
             mkdir -p $out
-            DTSDIR=$(mktemp -d /tmp/dts-XXXXXX)
-            cd $DTSDIR
             cp ${u-boot}/dts/zynq-${board}.dts .
 
             if [ ${board} == "zc706" ]; then
@@ -286,7 +285,6 @@
 
             dtc -I dts -O dtb -o ${board}.dtb zynq-${board}.dts
             cp ${board}.dtb $out
-            rm -rf $DTSDIR
           '';
 
         sd-image = let