[X86] Move the AC_EVEX_2_VEX AsmComments enum to X86InstrInfo.h from X86InstComments.h.

X86InstComments.h is used by tools that only have the MC layer. We shouldn't be importing a file from CodeGen into this.

X86InstrInfo.h isn't a great place, but I couldn't find a better one.

llvm-svn: 327202
diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
index f5f87c1..70949ba 100644
--- a/llvm/lib/Target/X86/X86MCInstLower.cpp
+++ b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -1454,7 +1454,7 @@
   // Add a comment about EVEX-2-VEX compression for AVX-512 instrs that
   // are compressed from EVEX encoding to VEX encoding.
   if (TM.Options.MCOptions.ShowMCEncoding) {
-    if (MI->getAsmPrinterFlags() & AC_EVEX_2_VEX)
+    if (MI->getAsmPrinterFlags() & X86::AC_EVEX_2_VEX)
       OutStreamer->AddComment("EVEX TO VEX Compression ", false);
   }