haskell.compiler.ghc967: bootstrap with GHC 9.4.8

We’d want every version to be able to trace back to 9.4.8 for the
“cross‐compiled GHC bootstrap tarballs” plan, anyway. I’m not
sure whether we’d want a `ghc948Binary` package that also includes
the official tarballs, or just only use our cross‐compiled binary
distributions, but it will make sense to align the version used for
bootstrap regardless.

(cherry picked from commit da915f81ef)

pkgs/top-level/haskell-packages.nix

@@ -92,7 +92,7 @@ in
       };
       ghc94 = compiler.ghc948;
       ghc967 = callPackage ../development/compilers/ghc/9.6.7.nix {
-        bootPkgs = bb.packages.ghc924Binary;
+        bootPkgs = bb.packages.ghc948;
         inherit (buildPackages.python3Packages) sphinx;
         inherit (buildPackages.darwin) xattr autoSignDarwinBinariesHook;
         inherit buildTargetLlvmPackages llvmPackages;