exfat: update to 5.19.1

exfat: update to 5.19.1

Major changes are:
  4 cleanups & typos fixes.
  Add keep_last_dots mount option to allow access to paths
  with trailing dots.
  Avoid repetitive volume dirty bit set/clear to improve
  storage life time.
  Fix ->i_blocks truncation issue caused by wrong 32bit mask.
  Fix ->i_blocks truncation issue that still exists elsewhere.
  Fix missing REQ_SYNC in exfat_update_bhs().
  Fix referencing wrong parent directory information during rename.
  Fix slab-out-bounds in exat_clear_bitmap() reported from syzbot.
  Improve performance while zeroing a cluster with dirsync mount option.
  Introduce a sys_tz mount option to use system timezone.
  Move super block magic number to magic.h

Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>