move userspace to top level to facilitate overriding

src/default.nix

@@ -18,10 +18,11 @@ let
         initramfs_image = self.initramfs;
       };
       kernel        = self.callPackage ./kernel { };
-      initramfs     = self.callPackage ./initramfs {
       userspace = self.callPackage ./userspace {
         kernelname = "${self.kernel.version}-${self.platform_name}";
       };
+      initramfs     = self.callPackage ./initramfs {
+        inherit (self) userspace;
       };
     }))
   .overrideScope' overlay;

src/initramfs/default.nix

@@ -28,5 +28,4 @@ nixpkgsOnBuildForHost.stdenv.mkDerivation {
     popd
   '';
   dontInstall = true;
-  passthru = { inherit userspace kernel; };
 }

src/platform/kevin/default.nix

@@ -24,8 +24,7 @@
         '';
       });
 
-    initramfs = prev.initramfs.override {
-      userspace = prev.initramfs.passthru.userspace.override {
+    userspace = prev.userspace.override {
       # order matters!  this is also the order in which the modules are insmoded
       modules_insmod = [
         "drivers/video/backlight/pwm_bl.ko"
@@ -58,7 +57,6 @@
         "drivers/net/wireless/marvell/mwifiex/mwifiex.ko"
       ];
     };
-    };
 
     coreboot =
       let atf = final.nixpkgsOnBuildForHost.callPackage (import ./atf) {