Core: Shorten the _interpreterInstruction typedef

The class itself already acts as a namespace trailer, so '_interpreter'
isn't necessary. This also gets rid of a duplicate typedef in the
Interpreter_Tables.

Source/Core/Core/PowerPC/PPCTables.cpp

@@ -63,7 +63,7 @@ GekkoOPInfo *GetOpInfo(UGeckoInstruction _inst)
 	}
 }
 
-Interpreter::_interpreterInstruction GetInterpreterOp(UGeckoInstruction _inst)
+Interpreter::Instruction GetInterpreterOp(UGeckoInstruction _inst)
 {
 	const GekkoOPInfo *info = m_infoTable[_inst.OPCD];
 	if ((info->type & 0xFFFFFF) == OPTYPE_SUBTABLE)