ide: add struct ide_host (take 3)

* Add struct ide_host which keeps pointers to host's ports.

* Add ide_host_alloc[_all]() and ide_host_remove() helpers.

* Pass 'struct ide_host *host' instead of 'u8 *idx' to
  ide_device_add[_all]() and rename it to ide_host_register[_all]().

* Convert host drivers and core code to use struct ide_host.

* Remove no longer needed ide_find_port().

* Make ide_find_port_slot() static.

* Unexport ide_unregister().

v2:
* Add missing 'struct ide_host *host' to macide.c.

v3:
* Fix build problem in pmac.c (s/ide_alloc_host/ide_host_alloc/)
  (Noticed by Stephen Rothwell).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/arm/palm_bk3710.c b/drivers/ide/arm/palm_bk3710.c
index 545563b..24389a5 100644
--- a/drivers/ide/arm/palm_bk3710.c
+++ b/drivers/ide/arm/palm_bk3710.c
@@ -347,11 +347,10 @@
 {
 	struct clk *clk;
 	struct resource *mem, *irq;
-	ide_hwif_t *hwif;
+	struct ide_host *host;
 	unsigned long base, rate;
 	int i;
 	hw_regs_t hw, *hws[] = { &hw, NULL, NULL, NULL };
-	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
 
 	clk = clk_get(NULL, "IDECLK");
 	if (IS_ERR(clk))
@@ -393,15 +392,11 @@
 	hw.irq = irq->start;
 	hw.chipset = ide_palm3710;
 
-	hwif = ide_find_port();
-	if (hwif == NULL)
+	host = ide_host_alloc(&palm_bk3710_port_info, hws);
+	if (host == NULL)
 		goto out;
 
-	i = hwif->index;
-
-	idx[0] = i;
-
-	ide_device_add(idx, &palm_bk3710_port_info, hws);
+	ide_host_register(host, &palm_bk3710_port_info, hws);
 
 	return 0;
 out: