[libata ahci] minor remove/unplug path cleanup

Don't bother calling a hook, to call our own module, to call a helper
than simply calls ionumap().

If you unroll all that convolution, you get a simple kfree()+iounmap()
pair of calls.
diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 179c95c..46e5f18 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -189,7 +189,6 @@
 static void ahci_eng_timeout(struct ata_port *ap);
 static int ahci_port_start(struct ata_port *ap);
 static void ahci_port_stop(struct ata_port *ap);
-static void ahci_host_stop(struct ata_host_set *host_set);
 static void ahci_tf_read(struct ata_port *ap, struct ata_taskfile *tf);
 static void ahci_qc_prep(struct ata_queued_cmd *qc);
 static u8 ahci_check_status(struct ata_port *ap);
@@ -242,7 +241,6 @@
 
 	.port_start		= ahci_port_start,
 	.port_stop		= ahci_port_stop,
-	.host_stop		= ahci_host_stop,
 };
 
 static struct ata_port_info ahci_port_info[] = {
@@ -301,14 +299,6 @@
 	return (void *) ahci_port_base_ul((unsigned long)base, port);
 }
 
-static void ahci_host_stop(struct ata_host_set *host_set)
-{
-	struct ahci_host_priv *hpriv = host_set->private_data;
-	kfree(hpriv);
-
-	ata_host_stop(host_set);
-}
-
 static int ahci_port_start(struct ata_port *ap)
 {
 	struct device *dev = ap->host_set->dev;
@@ -1089,7 +1079,8 @@
 		scsi_host_put(ap->host);
 	}
 
-	host_set->ops->host_stop(host_set);
+	kfree(hpriv);
+	iounmap(host_set->mmio_base);
 	kfree(host_set);
 
 	if (have_msi)
@@ -1106,7 +1097,6 @@
 	return pci_module_init(&ahci_pci_driver);
 }
 
-
 static void __exit ahci_exit(void)
 {
 	pci_unregister_driver(&ahci_pci_driver);