libata: use ata_id_c_string()

There were several places where ATA ID strings are manually terminated
and in some places possibly unterminated strings were passed to string
functions which don't limit length like strstr().  This patch converts
all of them over to ata_id_c_string().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>