scsi: aacraid: Fix error handling paths in aac_probe_one()

If 'scsi_host_alloc()' or 'kcalloc()' fail, 'error' is known to be 0. Set
it explicitly to -ENOMEM before branching to the error handling path.

While at it, remove 2 useless assignments to 'error'. These values are
overwridden a few lines later.

Link: https://lore.kernel.org/r/20200412094039.8822-1-christophe.jaillet@wanadoo.fr


Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>