python: Get rid of the VectorPort constructor.

The only thing it was doing beyond calling the parent Port __init__ was
to set isVec, and nobody actually looks at that value later.

Change-Id: I567cb583e6f02a6c18504b9bb20dd13b3c934822
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18175
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/python/m5/params.py

@@ -2115,11 +2115,6 @@ class ResponsePort(Port):
 # VectorPort description object.  Like Port, but represents a vector
 # of connections (e.g., as on a XBar).
 class VectorPort(Port):
-    # VectorPort("role", "description")
-    def __init__(self, role, desc, is_source=False):
-        super(VectorPort, self).__init__(role, desc, is_source)
-        self.isVec = True
-
     def makeRef(self, simobj):
         return VectorPortRef(simobj, self.name, self.role, self.is_source)