staging: exfat: drop local TRUE/FALSE defines

Replace with bool where it makes sense. Also drop unused local
variable lossy in fat_find_dir_entry.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Link: https://lore.kernel.org/r/20190903185537.25099-1-vvidic@valentin-vidic.from.hr


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