Remove unnecessary implicitTrunc use

Author: nikic

mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp

@@ -1284,8 +1284,7 @@ LogicalResult spirv::Deserializer::processConstant(ArrayRef<uint32_t> operands,
         uint32_t word1;
         uint32_t word2;
       } words = {operands[2], operands[3]};
-      value = APInt(64, llvm::bit_cast<uint64_t>(words), /*isSigned=*/true,
-                    /*implicitTrunc=*/true);
+      value = APInt(64, llvm::bit_cast<uint64_t>(words), /*isSigned=*/true);
     } else if (bitwidth <= 32) {
       value = APInt(bitwidth, operands[2], /*isSigned=*/true,
                     /*implicitTrunc=*/true);