chiaki: use nanopb from nixpkgs

chiaki currently uses a vendored nanopb that fails to build with the
version of protobuf in nixpkgs. If nanopb is supplied in buildInputs,
the build uses that instead, which resolves the issue. (same fix as
this one on chiaki-ng https://github.com/NixOS/nixpkgs/pull/404622)

Also remove the python and protobuf inputs, since they were only used
for building the vendored nanopb

pkgs/games/chiaki/default.nix

@@ -4,8 +4,6 @@
   fetchgit,
   cmake,
   pkg-config,
-  protobuf,
-  python3Packages,
   ffmpeg,
   libopus,
   mkDerivation,
@@ -16,6 +14,7 @@
   libevdev,
   udev,
   qtmacextras,
+  nanopb,
 }:
 
 mkDerivation rec {
@@ -32,10 +31,6 @@ mkDerivation rec {
   nativeBuildInputs = [
     cmake
     pkg-config
-    protobuf
-    python3Packages.protobuf
-    python3Packages.python
-    python3Packages.setuptools
   ];
 
   buildInputs =
@@ -45,8 +40,8 @@ mkDerivation rec {
       qtbase
       qtmultimedia
       qtsvg
-      protobuf
       SDL2
+      nanopb
     ]
     ++ lib.optionals stdenv.hostPlatform.isLinux [
       libevdev