csiostor: fix an error code in csio_hw_init()

We should return -ENOMEM if kzalloc() fails here instead of returning
success.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>