cpu,fastmodel: Eliminate the now unnecessary initMemProxies method.

The proxies this method initializes no longer exist, since they're now
created locally.

Change-Id: I5fd1c99fbc00f5057ea8868e91be02d577b1c176
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45909
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/cpu/simple_thread.hh

@@ -216,12 +216,6 @@ class SimpleThread : public ThreadState, public ThreadContext
 
     System *getSystemPtr() override { return system; }
 
-    void
-    initMemProxies(ThreadContext *tc) override
-    {
-        ThreadState::initMemProxies(tc);
-    }
-
     Process *getProcessPtr() override { return ThreadState::getProcessPtr(); }
     void setProcessPtr(Process *p) override { ThreadState::setProcessPtr(p); }