ata: Detect Delkin Devices compact flash

I have a Delkin Devices compact flash card that isn't being recognized using the
SATA/PATA drivers.
The card is recognized and works with the deprecated ATA drivers.

The error I am seeing is:
ata1.00: failed to IDENTIFY (device reports invalid type, err_mask=0x0)

I tracked it down to ata_id_is_cfa() in include/linux/ata.h.
The Delkin card has id[0] set to 0x844a and id[83] set to 0.
This isn't what the kernel expects and is probably incorrect.

The simplest work-around is to add a check for 0x844a to ata_id_is_cfa().

Signed-off-by: Ben Gardner <gardner.ben@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>