SCSI: remove fake "address-of" expression

Fake "address-of" expressions that evaluate to NULL generally confuse
readers and can provoke compiler warnings.  This patch (as1411) removes
one such fake expression, using an "#ifdef" in its place.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>