SCSI: zalon: fix oops on attach failure

commit d3a263a8168f78874254ea9da9595cfb0f3e96d7 upstream.

I recently discovered on my zalon that if the attachment fails because
of a bus misconfiguration (I scrapped my HVD array, so the card is now
unterminated) then the system oopses.  The reason is that if
ncr_attach() returns NULL (signalling failure) that NULL is passed by
the goto failed straight into ncr_detach() which oopses.

The fix is just to return -ENODEV in this case.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>