[Verifier] Remove redundant null-check (NFC) (#157458)

Fixes #157448

Author: apach301

llvm/lib/IR/Verifier.cpp

@@ -3185,7 +3185,7 @@ void Verifier::visitFunction(const Function &F) {
 
     // Scope and SP could be the same MDNode and we don't want to skip
     // validation in that case
-    if (SP && ((Scope != SP) && !Seen.insert(SP).second))
+    if ((Scope != SP) && !Seen.insert(SP).second)
       return;
 
     CheckDI(SP->describes(&F),