[clang][BPF] Update comment to include TYPE_MATCH

D126838 added support for the TYPE_MATCH compile-once run-everywhere
relocation to LLVM proper. On the clang side no changes are necessary,
other than the adjustment of a comment to mention this relocation as well.
This change takes care of that.

Differential Revision: https://reviews.llvm.org/D126839

clang/lib/Sema/SemaChecking.cpp

@@ -3254,7 +3254,7 @@ static bool isValidBPFPreserveTypeInfoArg(Expr *Arg) {
   if (ArgType->getAsPlaceholderType())
     return false;
 
-  // for TYPE_EXISTENCE/TYPE_SIZEOF reloc type
+  // for TYPE_EXISTENCE/TYPE_MATCH/TYPE_SIZEOF reloc type
   // format:
   //   1. __builtin_preserve_type_info(*(<type> *)0, flag);
   //   2. <type> var;