libata: stop overloading port_info->private_data

port_info->private_data is currently used for two purposes - to record
private data about the port_info or to specify host->private_data to
use when allocating ata_host.

This overloading is confusing and counter-intuitive in that
port_info->private_data becomes host->private_data instead of
port->private_data.  In addition, port_info and host don't correspond
to each other 1-to-1.  Currently, the first non-NULL
port_info->private_data is used.

This patch makes port_info->private_data just be what it is -
private_data for the port_info where LLD can jot down extra info.
libata no longer sets host->private_data to the first non-NULL
port_info->private_data, @host_priv argument is added to
ata_pci_init_one() instead.  LLDs which use ata_pci_init_one() can use
this argument to pass in pointer to host private data.  LLDs which
don't should use init-register model anyway and can initialize
host->private_data directly.

Adding @host_priv instead of using init-register model for LLDs which
use ata_pci_init_one() is suggested by Alan Cox.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
diff --git a/drivers/ata/pata_sis.c b/drivers/ata/pata_sis.c
index 32be13b..28abfc2 100644
--- a/drivers/ata/pata_sis.c
+++ b/drivers/ata/pata_sis.c
@@ -690,8 +690,7 @@
 static int sis_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	static int printed_version;
-	struct ata_port_info port;
-	const struct ata_port_info *ppi[] = { &port, NULL };
+	const struct ata_port_info *ppi[] = { NULL, NULL };
 	struct pci_dev *host = NULL;
 	struct sis_chipset *chipset = NULL;
 	struct sis_chipset *sets;
@@ -831,12 +830,11 @@
 	if (chipset == NULL)
 		return -ENODEV;
 
-	port = *chipset->info;
-	port.private_data = chipset;
+	ppi[0] = chipset->info;
 
 	sis_fixup(pdev, chipset);
 
-	return ata_pci_init_one(pdev, ppi, &sis_sht);
+	return ata_pci_init_one(pdev, ppi, &sis_sht, chipset);
 }
 
 static const struct pci_device_id sis_pci_tbl[] = {