libata: implement ata_host_alloc_pinfo() and ata_host_register()

Implement ata_host_alloc_pinfo() and ata_host_register().  These helpers
will be used in the following patches to adopt new init model.

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