Update Linux 3.15 to 3.15.3

pkgs/os-specific/linux/kernel/linux-3.15.nix

···
 { stdenv, fetchurl, ... } @ args:
 
 import ./generic.nix (args // rec {
-  version = "3.15.2";
+  version = "3.15.3";
   extraMeta.branch = "3.15";
 
   src = fetchurl {
     url = "mirror://kernel/linux/kernel/v3.x/linux-${version}.tar.xz";
-    sha256 = "09nq8q84xn6lwzdnn36pzfiqhn1lapi60yxn4hifb7v9ymhc5sv6";
+    sha256 = "0i8dmx1yiaraxb7gsjm7wpy0rv8038nbrwl2slzq749pgm4bd5bf";
   };
 
   features.iwlwifi = true;