[BOLT][NFC] Remove another unused function (#89011)

RewriteInstance::isKSymtabSection() is deprecated.

Author: maksfb

bolt/include/bolt/Rewrite/RewriteInstance.h

@@ -391,9 +391,6 @@ class RewriteInstance {
   /// Return true if the section holds debug information.
   static bool isDebugSection(StringRef SectionName);
 
-  /// Return true if the section holds linux kernel symbol information.
-  static bool isKSymtabSection(StringRef SectionName);
-
   /// Adds Debug section to overwrite.
   static void addToDebugSectionsToOverwrite(const char *Section) {
     DebugSectionsToOverwrite.emplace_back(Section);

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -5767,10 +5767,3 @@ bool RewriteInstance::isDebugSection(StringRef SectionName) {
 
   return false;
 }
-
-bool RewriteInstance::isKSymtabSection(StringRef SectionName) {
-  if (SectionName.starts_with("__ksymtab"))
-    return true;
-
-  return false;
-}