libata: update atapi_eh_request_sense() such that lbam/lbah contains buffer size

While updating lbam/h for ATAPI commands, atapi_eh_request_sense() was
left out.  Update it.

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