cpu-o3: block second uBTB block when conditional appears

Change-Id: Ife53cf3c2b710eb1167e3798a39d1af98976f97a

Author: Yakkhini

src/cpu/pred/btb/decoupled_bpred.cc

@@ -218,15 +218,12 @@ DecoupledBPUWithBTB::shouldGenerateSecondFromUBTB(
         return false;
     }
 
-    // Guard against history pollution: no conditional branch is allowed
-    // before the terminating taken branch in the second block.
+    // Guard against history pollution: second block should not contain any
+    // conditional branch when second-direction prediction is disabled.
     for (const auto &entry : ubtbPred.btbEntries) {
         if (!entry.valid) {
             continue;
         }
-        if (entry.pc == takenEntry.pc) {
-            break;
-        }
         if (entry.isCond) {
             return false;
         }