kgpe: add missing `mkdir` and path component

src/platform/kgpe/default.nix

@@ -20,8 +20,9 @@ in
 
     userspace = prev.userspace.overrideAttrs (a: {
       postInstall = (a.postInstall or "") + ''
-        cp ${final.coreboot.src}/mainboard/asus/kgpe-d16/cmos.layout $out/etc/
+        mkdir -p $out/etc
-        cp ${final.coreboot.src}/mainboard/asus/kgpe-d16/cmos.default $out/etc/
+        cp ${final.coreboot.src}/src/mainboard/asus/kgpe-d16/cmos.layout $out/etc/
+        cp ${final.coreboot.src}/src/mainboard/asus/kgpe-d16/cmos.default $out/etc/
       '';
     });