binwalk: simplify visualizationSupport code

pkgs/development/python-modules/binwalk/default.nix

@@ -17,10 +17,10 @@
 , matplotlib
 , nose
 , pycrypto
-, pyqtgraph ? null }:
+, pyqtgraph
+, visualizationSupport ? false }:
 
 let
-  visualizationSupport = (pyqtgraph != null) && (matplotlib != null);
   version = "2.2.0";
 in
 buildPythonPackage {

pkgs/top-level/python-packages.nix

@@ -931,14 +931,10 @@ in {
 
   binho-host-adapter = callPackage ../development/python-modules/binho-host-adapter { };
 
-  binwalk = callPackage ../development/python-modules/binwalk {
-    pyqtgraph = null;
-    matplotlib = null;
-  };
+  binwalk = callPackage ../development/python-modules/binwalk { };
 
   binwalk-full = appendToName "full" (self.binwalk.override {
-    pyqtgraph = self.pyqtgraph;
-    matplotlib = self.matplotlib;
+    visualizationSupport = true;
   });
 
   biopython = callPackage ../development/python-modules/biopython { };