release-lib: Avoid filtering twice

We were using `supportedMatches` both when getting the list of
platforms, and before `genAttrs` the derivation for each. Now we just
filter the second time,

pkgs/top-level/release-lib.nix

@@ -145,7 +145,7 @@ rec {
     let res = builtins.tryEval (
       if isDerivation value then
         value.meta.hydraPlatforms
-          or (supportedMatches (value.meta.platforms or [ "x86_64-linux" ]))
+          or (value.meta.platforms or [ "x86_64-linux" ])
       else if value.recurseForDerivations or false || value.recurseForRelease or false then
         packagePlatforms value
       else