t14s: add AMD Gen1 model

t14s: fix minimum required kernel version

lenovo/thinkpad/t14s/amd/default.nix

@@ -0,0 +1,11 @@
+{ config, lib, pkgs, ... }:
+
+{
+  imports = [
+    ../.
+    ../../../../common/cpu/amd
+  ];
+
+  # For support of newer AMD GPUs, backlight and internal microphone
+  boot.kernelPackages = lib.mkIf (lib.versionOlder pkgs.linux.version "5.8") pkgs.linuxPackages_latest;
+}