uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/tools/misc/grub/pvgrub_image/configs/grub-bootstrap.cfg

@@ -0,0 +1 @@
+normal (memdisk)/grub.cfg

pkgs/tools/misc/grub/pvgrub_image/configs/grub.cfg

@@ -0,0 +1,10 @@
+# The parentheses around ${root} here to match Grub's config file syntax
+if search -s -f /boot/grub/grub.cfg ; then
+        echo "Reading (${root})/boot/grub/grub.cfg"
+	configfile /boot/grub/grub.cfg
+fi
+
+if search -s -f /grub/grub.cfg ; then
+	echo "Reading (${root})/grub/grub.cfg"
+	configfile /grub/grub.cfg
+fi

pkgs/tools/misc/grub/pvgrub_image/default.nix

@@ -0,0 +1,42 @@
+{ lib, stdenv, grub2_xen }:
+
+with lib;
+let
+  efiSystemsBuild = {
+    i686-linux.target = "i386";
+    x86_64-linux.target = "x86_64";
+    aarch64-linux.target = "aarch64";
+  };
+
+in (
+
+stdenv.mkDerivation rec {
+  name = "pvgrub-image";
+
+  configs = ./configs;
+
+  buildInputs = [ grub2_xen ];
+
+  buildCommand = ''
+    cp "${configs}"/* .
+    tar -cf memdisk.tar grub.cfg
+    # We include all modules except all_video.mod as otherwise grub will fail printing "no symbol table"
+    # if we include it.
+    grub-mkimage -O "${efiSystemsBuild.${stdenv.hostPlatform.system}.target}-xen" -c grub-bootstrap.cfg \
+      -m memdisk.tar -o "grub-${efiSystemsBuild.${stdenv.hostPlatform.system}.target}-xen.bin" \
+      $(ls "${grub2_xen}/lib/grub/${efiSystemsBuild.${stdenv.hostPlatform.system}.target}-xen/" |grep 'mod''$'|grep -v '^all_video\.mod''$')
+    mkdir -p "$out/lib/grub-xen"
+    cp "grub-${efiSystemsBuild.${stdenv.hostPlatform.system}.target}-xen.bin" $out/lib/grub-xen/
+  '';
+
+  meta = with lib; {
+    description = "PvGrub image for use for booting PV Xen guests";
+
+    longDescription =
+      '' This package provides a PvGrub image for booting Para-Virtualized (PV)
+         Xen guests
+      '';
+
+    platforms = platforms.gnu ++ platforms.linux;
+  };
+})