cryptsetup: enable kernel crypto api support again

This is needed for tcrypt and the benchmark subcommand. If enabled,
it is also used to unlock LUKS2 volumes and therefore the kernel modules
providing this feature need to be available in our initrd.

Fixes #42163. #54019.

nixos/modules/system/boot/luksroot.nix

@@ -438,6 +438,7 @@ in
       default =
         [ "aes" "aes_generic" "blowfish" "twofish"
           "serpent" "cbc" "xts" "lrw" "sha1" "sha256" "sha512"
+          "af_alg" "algif_skcipher"
 
           (if pkgs.stdenv.hostPlatform.system == "x86_64-linux" then "aes_x86_64" else "aes_i586")
         ];

pkgs/os-specific/linux/cryptsetup/default.nix

@@ -32,7 +32,6 @@ stdenv.mkDerivation rec {
   NIX_LDFLAGS = "-lgcc_s";
 
   configureFlags = [
-    "--disable-kernel_crypto"
     "--enable-cryptsetup-reencrypt"
     "--with-crypto_backend=openssl"
   ] ++ stdenv.lib.optional enablePython "--enable-python";