fs/affs/super.c: fix switch indentation

Fix checkpatch error:

  ERROR: switch and case should be at the same indent
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>