linux_libre: remove cruft

follow up from https://github.com/NixOS/nixpkgs/commit/545a975d7e225d6315080aee7e82cee5a133fb51

nixos/tests/kernel-generic/default.nix

@@ -84,7 +84,6 @@ let
       linux_rt_5_15
       linux_rt_6_1
       linux_rt_6_6
-      linux_libre
 
       linux_testing
       ;

pkgs/os-specific/linux/amdgpu-i2c/default.nix

@@ -32,7 +32,7 @@ stdenv.mkDerivation {
     homepage = "https://github.com/twifty/amd-gpu-i2c";
     downloadPage = "https://github.com/twifty/amd-gpu-i2c";
     description = "Exposes i2c interface to set colors on AMD GPUs";
-    broken = kernel.kernelOlder "6.1.0" || kernel.isLibre;
+    broken = kernel.kernelOlder "6.1.0";
     license = lib.licenses.gpl2Plus;
     platforms = lib.platforms.linux;
     maintainers = with lib.maintainers; [ thardin ];

pkgs/os-specific/linux/kernel/build.nix

@@ -77,7 +77,6 @@ lib.makeOverridable (
 
     # for module compatibility
     isZen ? false,
-    isLibre ? false,
     isHardened ? false,
 
     # Whether to utilize the controversial import-from-derivation feature to parse the config
@@ -526,7 +525,6 @@ lib.makeOverridable (
       inherit
         isZen
         isHardened
-        isLibre
         withRust
         ;
       isXen = lib.warn "The isXen attribute is deprecated. All Nixpkgs kernels that support it now have Xen enabled." true;

pkgs/os-specific/linux/kernel/generic.nix

@@ -75,7 +75,6 @@ lib.makeOverridable (
 
     isLTS ? false,
     isZen ? false,
-    isLibre ? false,
     isHardened ? false,
 
     # easy overrides to stdenv.hostPlatform.linux-kernel members
@@ -317,7 +316,6 @@ lib.makeOverridable (
             isLTS
             isZen
             isHardened
-            isLibre
             ;
           isXen = lib.warn "The isXen attribute is deprecated. All Nixpkgs kernels that support it now have Xen enabled." true;
 

pkgs/top-level/linux-kernels.nix

@@ -329,7 +329,6 @@ in
           isLTS
           isZen
           isHardened
-          isLibre
           ;
         inherit (kernel) kernelOlder kernelAtLeast;
         kernelModuleMakeFlags = self.kernel.commonMakeFlags ++ [