coreboot-toolchain: Disable fetching of submodules

Submodules are not needed. Thus, disable fetching of the submodules.

Signed-off-by: Felix Singer <felixsinger@posteo.net>

pkgs/development/tools/misc/coreboot-toolchain/default.nix

@@ -11,6 +11,7 @@ stdenvNoCC.mkDerivation rec {
     url = "https://review.coreboot.org/coreboot";
     rev = version;
     sha256 = "00xr74yc0kj9rrqa1a8b7bih865qlp9i4zs67ysavkfrjrwwssxm";
+    fetchSubmodules = false;
   };
 
   nativeBuildInputs = [ bison curl git perl ];