linuxKernel.kernels.4_*.phc-intel: remove support

phc-intel flavor is unused because 4.x support is deprecated

Removed all references of 'phc-intel' from the codebase and
add removal notice

pkgs/os-specific/linux/phc-intel/default.nix

@@ -1,62 +0,0 @@
-{
-  lib,
-  stdenv,
-  fetchurl,
-  kernel,
-  which,
-}:
-
-# Don't bother with older versions, though some might even work:
-assert lib.versionAtLeast kernel.version "4.10";
-
-let
-  release = "0.4.0";
-  revbump = "rev25"; # don't forget to change forum download id...
-in
-stdenv.mkDerivation rec {
-  name = "linux-phc-intel-${version}-${kernel.version}";
-  version = "${release}-${revbump}";
-
-  src = fetchurl {
-    sha256 = "1w91hpphd8i0br7g5qra26jdydqar45zqwq6jq8yyz6l0vb10zlz";
-    url = "http://www.linux-phc.org/forum/download/file.php?id=194";
-    name = "phc-intel-pack-${revbump}.tar.bz2";
-  };
-
-  nativeBuildInputs = [ which ] ++ kernel.moduleBuildDependencies;
-
-  hardeningDisable = [ "pic" ];
-
-  makeFlags = with kernel; [
-    "DESTDIR=$(out)"
-    "KERNELSRC=${dev}/lib/modules/${modDirVersion}/build"
-  ];
-
-  configurePhase = ''
-    make $makeFlags brave
-  '';
-
-  enableParallelBuilding = false;
-
-  installPhase = ''
-    install -m 755   -d $out/lib/modules/${kernel.modDirVersion}/extra/
-    install -m 644 *.ko $out/lib/modules/${kernel.modDirVersion}/extra/
-  '';
-
-  meta = with lib; {
-    description = "Undervolting kernel driver for Intel processors";
-    longDescription = ''
-      PHC is a Linux kernel patch to undervolt processors. This can divide the
-      power consumption of the CPU by two or more, increasing battery life
-      while noticably reducing fan noise. This driver works only on supported
-      Intel architectures.
-    '';
-    homepage = "https://github.com/danielw86dev/phc-intel-dkms";
-    license = licenses.gpl2Plus;
-    platforms = [
-      "x86_64-linux"
-      "i686-linux"
-    ];
-    broken = lib.versionAtLeast kernel.version "4.18";
-  };
-}

pkgs/top-level/linux-kernels.nix

@@ -587,12 +587,6 @@ in
 
         perf = callPackage ../os-specific/linux/kernel/perf { };
 
-        phc-intel =
-          if lib.versionAtLeast kernel.version "4.10" then
-            callPackage ../os-specific/linux/phc-intel { }
-          else
-            null;
-
         prl-tools = callPackage ../os-specific/linux/prl-tools { };
 
         isgx = callPackage ../os-specific/linux/isgx { };
@@ -721,6 +715,7 @@ in
         system76-power = lib.warnOnInstantiate "kernelPackages.system76-power is now pkgs.system76-power" pkgs.system76-power; # Added 2024-10-16
         system76-scheduler = lib.warnOnInstantiate "kernelPackages.system76-scheduler is now pkgs.system76-scheduler" pkgs.system76-scheduler; # Added 2024-10-16
         tuxedo-keyboard = self.tuxedo-drivers; # Added 2024-09-28
+        phc-intel = throw "phc-intel drivers are no longer supported by any kernel >=4.17"; # added 2025-07-18
       }
     );