[rtl vvau]: minor fix to dsp estimation

Author: mmrahorovic

src/finn/custom_op/fpgadataflow/rtl/vectorvectoractivation_rtl.py

@@ -144,8 +144,9 @@ def lut_estimation(self):
         return 0
 
     def dsp_estimation(self):
+        P = self.get_nodeattr("PE")
         Q = self.get_nodeattr("SIMD")
-        return int(np.ceil(Q / 3))
+        return int(P * np.ceil(Q / 3))
 
     def instantiate_ip(self, cmd):
         # instantiate the RTL IP