Kernel: Remove empty ISO9660Inode::one_ref_left()

Kernel/FileSystem/ISO9660FileSystem.cpp

@@ -552,10 +552,6 @@ ErrorOr<void> ISO9660Inode::set_mtime(time_t)
     return EROFS;
 }
 
-void ISO9660Inode::one_ref_left()
-{
-}
-
 ISO9660Inode::ISO9660Inode(ISO9660FS& fs, ISO::DirectoryRecordHeader const& record, StringView name)
     : Inode(fs, get_inode_index(record, name))
     , m_record(record)

Kernel/FileSystem/ISO9660FileSystem.h

@@ -362,7 +362,6 @@ public:
     virtual ErrorOr<void> set_atime(time_t) override;
     virtual ErrorOr<void> set_ctime(time_t) override;
     virtual ErrorOr<void> set_mtime(time_t) override;
-    virtual void one_ref_left() override;
 
 private:
     // HACK: The base ISO 9660 standard says the maximum filename length is 37