dev,cpu,configs: Get rid of the IntrControl device.

This vestigial device provides a thin layer of indirection between
devices and the CPUs in a system. It's basically a collection of helper
functions, but since it's a SimObject it needs to be instantiated in
python and added to configurations.

Change-Id: I029d2314ae0bb890678e1e68dafcdab4bfe49beb
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/43347
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/platform.cc

@@ -29,16 +29,8 @@
 #include "dev/platform.hh"
 
 #include "base/logging.hh"
-#include "sim/sim_exit.hh"
 
-Platform::Platform(const Params &p)
-    : SimObject(p), intrctrl(p.intrctrl)
-{
-}
-
-Platform::~Platform()
-{
-}
+Platform::Platform(const Params &p) : SimObject(p), system(p.system) {}
 
 void
 Platform::postPciInt(int line)