Revert "microcodeIntel: 20171117 -> 20170108"

This reverts commit 9b7ef9c738e743992ef268beba13d52bcc8a0b04.

Intel recommends to stop deployment of the updated microcode as it
introduces unexpected system behaviour on many platforms.

See https://security-center.intel.com/advisory.aspx?intelid=INTEL-SA-00088&languageid=en-fr

cc #33414

pkgs/os-specific/linux/microcode/intel.nix

···
 
 stdenv.mkDerivation rec {
   name = "microcode-intel-${version}";
-  version = "20180108";
+  version = "20171117";
 
   src = fetchurl {
-    url = "https://downloadmirror.intel.com/27431/eng/microcode-${version}.tgz";
-    sha256 = "0c214238mjks07zwif07f4041c74jil522sy78r4kjs6lniilgq6";
+    url = "https://downloadmirror.intel.com/27337/eng/microcode-${version}.tgz";
+    sha256 = "1p14ypbg28bdkbza6dx6dpjrdr5p13vmgrh2cw0y1v2qzalivgck";
   };
 
   buildInputs = [ libarchive ];