staging: exfat: cleanup braces for if/else statements

Fixes checkpatch.pl warnings:

  CHECK: Unbalanced braces around else statement
  CHECK: braces {} should be used on all arms of this statement

Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Link: https://lore.kernel.org/r/20190903164732.14194-1-vvidic@valentin-vidic.from.hr


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