arch,arch-x86: Consolidate the add_microop method.

This was defined in the Micro_Container base class, and then again in
each subclass. The base definition was different and less complete than
the others, but the others were identical. Replace the base class
definition with the definition in the subclasses, and delete the ones in
the subclasses.

Change-Id: Ib2d1ce72958ec299115efb6efced2bd14c08467c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56330
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/micro_asm.py

@@ -49,6 +49,8 @@ class Micro_Container(object):
         self.labels = {}
 
     def add_microop(self, mnemonic, microop):
+        microop.mnemonic = mnemonic
+        microop.micropc = len(self.microops)
         self.microops.append(microop)
 
     def __str__(self):