[SCSI] aha152x: fix init suspiciously returned 1, it should follow 0/-E convention

Reported-by: Frank de Jong <frapex@xs4all.nl>
> [1.] One line summary of the problem:
> linux-2.6.25.3, aha152x'->init suspiciously returned 1, it should
> follow 0/-E convention. The module / driver works okay. Unloading the
> module is impossible.

The driver is apparently returning 0 on failure and 1 on success.
That's a bit unfortunate.  Fix it by altering to -ENODEV and 0.

Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>