s2io: use snprintf() as a safety feature

"sp->desc[i]" has 25 characters.  "dev->name" has 15 characters.  If we
used all 15 characters then the sprintf() would overflow.

I changed the "sprintf(sp->name, "%s Neterion %s"" to snprintf(), as
well, even though it can't overflow just to be consistent.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>