cciss: fix regression that no device nodes are created if no logical drives are configured.

Fix regression in cciss driver that if no logical drives are configured,
no device nodes at all get created.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
Acked-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>