[MLIR] Apply clang-tidy fixes for readability-simplify-boolean-expr in InlinerInterfaceImpl.cpp (NFC)

Author: joker-eph

mlir/lib/Dialect/LLVMIR/Transforms/InlinerInterfaceImpl.cpp

@@ -755,10 +755,8 @@ struct LLVMInlinerInterface : public DialectInlinerInterface {
 
   bool allowSingleBlockOptimization(
       iterator_range<Region::iterator> inlinedBlocks) const final {
-    if (!inlinedBlocks.empty() &&
-        isa<LLVM::UnreachableOp>(inlinedBlocks.begin()->getTerminator()))
-      return false;
-    return true;
+    return !(!inlinedBlocks.empty() &&
+             isa<LLVM::UnreachableOp>(inlinedBlocks.begin()->getTerminator()));
   }
 
   /// Handle the given inlined return by replacing the uses of the call with the