cpu: Move the branch predictor out of the BaseCPU

The branch predictor is guarded by having either the in-order or
out-of-order CPU as one of the available CPU models and therefore
should not be used in the BaseCPU. This patch moves the parameter to
the relevant CPU classes.

src/cpu/BaseCPU.py

@@ -51,7 +51,6 @@ from Bus import CoherentBus
 from InstTracer import InstTracer
 from ExeTracer import ExeTracer
 from MemObject import MemObject
-from BranchPredictor import BranchPredictor
 from ClockDomain import *
 
 default_tracer = ExeTracer()
@@ -210,8 +209,6 @@ class BaseCPU(MemObject):
     dcache_port = MasterPort("Data Port")
     _cached_ports = ['icache_port', 'dcache_port']
 
-    branchPred = Param.BranchPredictor(NULL, "Branch Predictor")
-
     if buildEnv['TARGET_ISA'] in ['x86', 'arm']:
         _cached_ports += ["itb.walker.port", "dtb.walker.port"]