staging: exfat: fix spelling errors in comments

Fixes checkpatch.pl warnings:

  CHECK: 'consistancy' may be misspelled - perhaps 'consistency'?
  CHECK: 'stuct' may be misspelled - perhaps 'struct'?

Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Link: https://lore.kernel.org/r/20190903165408.16010-1-vvidic@valentin-vidic.from.hr


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>