cpu, power: Get rid of the remnants of the EA computation insts.

Get rid of some remnants of a system which was intended to separate
address computation into its own instruction object.

Change-Id: I23f9ffd70fcb89a8ea5bbb934507fb00da9a0b7f
Reviewed-on: https://gem5-review.googlesource.com/7122
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/arch/power/isa/formats/mem.isa

@@ -98,7 +98,6 @@ def template LoadInitiateAcc {{
 
         if (fault == NoFault) {
             fault = initiateMemRead(xc, traceData, EA, Mem, memAccessFlags);
-            xc->setEA(EA);
         }
 
         return fault;
@@ -117,7 +116,7 @@ def template LoadCompleteAcc {{
         %(op_decl)s;
         %(op_rd)s;
 
-        EA = xc->getEA();
+        EA = pkt->req->getVaddr();
 
         getMem(pkt, Mem, traceData);