X86: Remove implicit ilist iterator conversions, NFC

llvm-svn: 250741
diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
index 263c133..2cda821 100644
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -298,8 +298,8 @@
     return false;
 
   // Make sure nothing is in the way
-  BasicBlock::const_iterator Start = I;
-  BasicBlock::const_iterator End = II;
+  BasicBlock::const_iterator Start(I);
+  BasicBlock::const_iterator End(II);
   for (auto Itr = std::prev(Start); Itr != End; --Itr) {
     // We only expect extractvalue instructions between the intrinsic and the
     // instruction to be selected.