openems: fix eval

pkgs/applications/science/electronics/openems/default.nix

···
 , withQcsxcad ? true
 , withMPI ? false
 , withHyp2mat ? true
-, qcsxcad ? null
-, hyp2mat ? null
+, qcsxcad
+, hyp2mat
 }:
-
-assert withQcsxcad -> qcsxcad != null;
-assert withHyp2mat -> hyp2mat != null;
 
 stdenv.mkDerivation {
   pname = "openems";

pkgs/top-level/all-packages.nix

···
 
   ngspice = callPackage ../applications/science/electronics/ngspice { };
 
-  openems = callPackage ../applications/science/electronics/openems { };
+  openems = callPackage ../applications/science/electronics/openems {
+    qcsxcad = libsForQt5.qcsxcad;
+  };
 
   openroad = libsForQt5.callPackage ../applications/science/electronics/openroad { };