[SCSI] aic7xxx/aic79xx: fix module removal path not to panic

In these drivers, scsi_remove_host() is called too late, at the point
it is called, the driver has already shut down too far to accept any
I/O that the shutdown might generate.  Any generated I/O actually
triggers a panic.

Fix this by calling scsi_remove_host() as early as possible and not
calling scsi_host_put() until just before we kfree the ahc_softc.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/aic7xxx/aic7770_osm.c b/drivers/scsi/aic7xxx/aic7770_osm.c
index 70c5fb5..d754b32 100644
--- a/drivers/scsi/aic7xxx/aic7770_osm.c
+++ b/drivers/scsi/aic7xxx/aic7770_osm.c
@@ -112,6 +112,9 @@
 	struct ahc_softc *ahc = dev_get_drvdata(dev);
 	u_long s;
 
+	if (ahc->platform_data && ahc->platform_data->host)
+			scsi_remove_host(ahc->platform_data->host);
+
 	ahc_lock(ahc, &s);
 	ahc_intr_enable(ahc, FALSE);
 	ahc_unlock(ahc, &s);