ide: use 'drive->dn & 1' instead of drive->select.b.unit

* Call ide_port_init_devices() in ide_host_register()
  also if 'struct ide_port_info *d' is not available.

* Init drive->dn in ide_port_init_devices() instead of
  ide_probe_port() so it is valid also in ->init_dev.

* Pass device number to ide_dev_apply_params().

* Use 'drive->dn & 1' instead of drive->select.b.unit.

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/opti621.c b/drivers/ide/pci/opti621.c
index 3de11dd..f0db38b 100644
--- a/drivers/ide/pci/opti621.c
+++ b/drivers/ide/pci/opti621.c
@@ -179,7 +179,7 @@
 	misc = addr_timings[clk][addr_pio];
 
 	/* select Index-0/1 for Register-A/B */
-	write_reg(drive->select.b.unit, MISC_REG);
+	write_reg(drive->dn & 1, MISC_REG);
 	/* set read cycle timings */
 	write_reg(tim, READ_REG);
 	/* set write cycle timings */