[llvm] [X86] Remove outdated comment (PR #133743)

[Mikołaj Piróg via llvm-commits]

================
@@ -371,8 +371,7 @@ def FeatureMOVRS   : SubtargetFeature<"movrs", "HasMOVRS", "true",
                            "Enable MOVRS", []>;
 
 // Ivy Bridge and newer processors have enhanced REP MOVSB and STOSB (aka
-// "string operations"). See "REP String Enhancement" in the Intel Software
----------------
mikolaj-pirog wrote:

Yes, thanks for the find! I still feel it's better to remove it, but if others feel it's better to update it, I will update it

https://github.com/llvm/llvm-project/pull/133743