mgba: remove inherit (libsForQt5) reference on all-packages.nix

According to the issue linked at the end, filling arguments for `callPackage` in
all-packages.nix breaks splicing and makes the expressions incompatible with
cross-compilation.

This issue is more pronounced in the many `inherit (darwin)` calls. However, it
is present in similar contexts too.

The idea here is not the smartest: it just hides those inheritances from
`all-packages.nix` and sends them to the `default.nix` expressions.

Issue: https://github.com/NixOS/nixpkgs/issues/204303

pkgs/applications/emulators/mgba/default.nix

@@ -3,21 +3,27 @@
 , fetchFromGitHub
 , SDL2
 , cmake
-, ffmpeg
+, ffmpeg_4
 , imagemagick
 , libedit
 , libelf
 , libepoxy
 , libzip
-, lua
+, lua5_4
 , minizip
 , pkg-config
-, qtbase
-, qtmultimedia
-, qttools
-, wrapQtAppsHook
+, libsForQt5
 }:
 
+let
+    ffmpeg = ffmpeg_4;
+    lua = lua5_4;
+    inherit (libsForQt5)
+      qtbase
+      qtmultimedia
+      qttools
+      wrapQtAppsHook;
+in
 stdenv.mkDerivation (finalAttrs: {
   pname = "mgba";
   version = "0.10.0";

pkgs/top-level/all-packages.nix

@@ -2068,13 +2068,6 @@ with pkgs;
   melonDS = libsForQt5.callPackage ../applications/emulators/melonDS { };
 
   mgba = callPackage ../applications/emulators/mgba {
-    ffmpeg = ffmpeg_4;
-    lua = lua5_4;
-    inherit (libsForQt5)
-      qtbase
-      qtmultimedia
-      qttools
-      wrapQtAppsHook;
   };
 
   mupen64plus = callPackage ../applications/emulators/mupen64plus { };