[SCSI] atari_NCR5380: Remove obsolete variable oldto

commit 8ce7955a

 ("[SCSI] atari_NCR5380:
update_timeout removal") removed all users, but not the avtual variable.

Suggested-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>