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_acpi.c b/drivers/ata/pata_acpi.c
index 3edde51..d337f32 100644
--- a/drivers/ata/pata_acpi.c
+++ b/drivers/ata/pata_acpi.c
@@ -68,20 +68,6 @@
 }
 
 /**
- *	pacpi_error_handler - Setup and error handler
- *	@ap: Port to handle
- *
- *	LOCKING:
- *	None (inherited from caller).
- */
-
-static void pacpi_error_handler(struct ata_port *ap)
-{
-	ata_bmdma_drive_eh(ap, pacpi_pre_reset, ata_std_softreset, NULL,
-			   ata_std_postreset);
-}
-
-/**
  *	pacpi_discover_modes	-	filter non ACPI modes
  *	@adev: ATA device
  *	@mask: proposed modes
@@ -242,7 +228,7 @@
 	.mode_filter		= pacpi_mode_filter,
 	.set_piomode		= pacpi_set_piomode,
 	.set_dmamode		= pacpi_set_dmamode,
-	.error_handler		= pacpi_error_handler,
+	.prereset		= pacpi_pre_reset,
 	.port_start		= pacpi_port_start,
 };
 
@@ -273,7 +259,7 @@
 		.port_ops	= &pacpi_ops,
 	};
 	const struct ata_port_info *ppi[] = { &info, NULL };
-	return ata_pci_init_one(pdev, ppi, &pacpi_sht);
+	return ata_pci_init_one(pdev, ppi, &pacpi_sht, NULL);
 }
 
 static const struct pci_device_id pacpi_pci_tbl[] = {