More restructuring on Python config code for auto-generating

of Param structs.

objects/CoherenceProtocol.mpy:
objects/Ide.mpy:
    Update for new Enum syntax.
sim/pyconfig/m5config.py:
    More modest restructuring heading for auto-generating
    of param structs.

    - Revamped Enum handling: Enums are regular classes so they
    know their names now (makes it easier for generating C++
    equivalents).

    - Created MetaSimObject class and moved some SimObject-specific
    stuff there (i.e. does not apply to ConfigNodes in general).

--HG--
extra : convert_revision : a93b40dda3b038ebe8bffecac97e9079c22af561

objects/CoherenceProtocol.mpy

@@ -1,4 +1,4 @@
-Coherence = Enum('uni', 'msi', 'mesi', 'mosi', 'moesi')
+class Coherence(Enum): vals = ['uni', 'msi', 'mesi', 'mosi', 'moesi']
 
 simobj CoherenceProtocol(SimObject):
     type = 'CoherenceProtocol'

objects/Ide.mpy

@@ -1,6 +1,6 @@
 from Pci import PciDevice
 
-IdeID = Enum('master', 'slave')
+class IdeID(Enum): vals = ['master', 'slave']
 
 simobj IdeDisk(SimObject):
     type = 'IdeDisk'