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.hh

@@ -40,22 +40,18 @@
 #include "params/Platform.hh"
 #include "sim/sim_object.hh"
 
-class IntrControl;
 class Terminal;
 class Uart;
 class System;
 
-
 class Platform : public SimObject
 {
   public:
-    /** Pointer to the interrupt controller */
-    IntrControl *intrctrl;
+    System *system;
 
-  public:
     typedef PlatformParams Params;
     Platform(const Params &p);
-    virtual ~Platform();
+    virtual ~Platform() = default;
 
     /**
      * Cause the cpu to post a serial interrupt to the CPU.