Fix the name of a variable to match its declaration. Fixes build failure from r177014.

llvm-svn: 177015
diff --git a/llvm/lib/Target/X86/X86CodeEmitter.cpp b/llvm/lib/Target/X86/X86CodeEmitter.cpp
index a6bb2a7..5d9dfa9 100644
--- a/llvm/lib/Target/X86/X86CodeEmitter.cpp
+++ b/llvm/lib/Target/X86/X86CodeEmitter.cpp
@@ -1034,7 +1034,7 @@
       if (HasVEX_4V)
         VEX_4V = getVEXRegisterEncoding(MI, CurOp++);
 
-      if (MemOp4) // Skip second register source (encoded in I8IMM)
+      if (HasMemOp4) // Skip second register source (encoded in I8IMM)
         CurOp++;
 
       if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))