haskell.compiler.ghc981: drop

Latest 9.8.x minor release is 9.8.4, which is also in Stackage 23.28.

Thus, dropping according to the GHC Deprecation Policy.

pkgs/development/compilers/ghc/9.8.1.nix

@@ -1,4 +0,0 @@
-import ./common-hadrian.nix {
-  version = "9.8.1";
-  sha256 = "b2f8ed6b7f733797a92436f4ff6e088a520913149c9a9be90465b40ad1f20751";
-}

pkgs/development/compilers/ghc/common-hadrian.nix

@@ -281,7 +281,6 @@
       ++
         lib.optionals
           (lib.elem version [
-            "9.8.1"
             "9.8.2"
           ])
           [

pkgs/top-level/haskell-packages.nix

@@ -217,24 +217,6 @@ in
         llvmPackages = pkgs.llvmPackages_15;
       };
       ghc96 = compiler.ghc967;
-      ghc981 = callPackage ../development/compilers/ghc/9.8.1.nix {
-        bootPkgs =
-          # For GHC 9.6 no armv7l bindists are available.
-          if stdenv.buildPlatform.isAarch32 then
-            bb.packages.ghc963
-          else if stdenv.buildPlatform.isPower64 && stdenv.buildPlatform.isLittleEndian then
-            bb.packages.ghc963
-          else
-            bb.packages.ghc963Binary;
-        inherit (buildPackages.python3Packages) sphinx;
-        # Need to use apple's patched xattr until
-        # https://github.com/xattr/xattr/issues/44 and
-        # https://github.com/xattr/xattr/issues/55 are solved.
-        inherit (buildPackages.darwin) xattr autoSignDarwinBinariesHook;
-        # Support range >= 11 && < 16
-        buildTargetLlvmPackages = pkgsBuildTarget.llvmPackages_15;
-        llvmPackages = pkgs.llvmPackages_15;
-      };
       ghc982 = callPackage ../development/compilers/ghc/9.8.2.nix {
         bootPkgs =
           # For GHC 9.6 no armv7l bindists are available.
@@ -507,11 +489,6 @@ in
         compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-9.6.x.nix { };
       };
       ghc96 = packages.ghc967;
-      ghc981 = callPackage ../development/haskell-modules {
-        buildHaskellPackages = bh.packages.ghc981;
-        ghc = bh.compiler.ghc981;
-        compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-9.8.x.nix { };
-      };
       ghc982 = callPackage ../development/haskell-modules {
         buildHaskellPackages = bh.packages.ghc982;
         ghc = bh.compiler.ghc982;

pkgs/top-level/release-haskell.nix

@@ -69,7 +69,6 @@ let
     ghc948
     ghc963
     ghc967
-    ghc981
     ghc982
     ghc983
     ghc984