pyloxi: remove 'skip' field from Member

The other member types catch the ones that would previously set this flag.

The type fields of instructions, action_ids, etc still aren't populated.
diff --git a/py_gen/templates/oxm.py b/py_gen/templates/oxm.py
index 5d5df7a..e11a0a4 100644
--- a/py_gen/templates/oxm.py
+++ b/py_gen/templates/oxm.py
@@ -53,7 +53,7 @@
 
 :: for ofclass in ofclasses:
 :: from py_gen.codegen import Member, LengthMember, TypeMember
-:: normal_members = [m for m in ofclass.members if type(m) == Member and not m.skip]
+:: normal_members = [m for m in ofclass.members if type(m) == Member]
 :: type_members = [m for m in ofclass.members if type(m) == TypeMember]
 class ${ofclass.pyname}(OXM):
 :: for m in type_members: