ide: make legacy IDE VLB modules check for the "probe" kernel params (v2)

Legacy IDE VLB host drivers didn't check for "probe" options when compiled
as modules, which was obviously wrong as we don't want module to poke at
random I/O ports by simply loading it.  Fix it by adding "probe" module param
to legacy IDE VLB host drivers.

v2:
* don't obsolete old "ide0=dtc2278/ht6560b/qd65xx/ali14xx/umc8672"
  IDE driver options yet (per Alan Cox's request) and enhance documentation

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/legacy/umc8672.c b/drivers/ide/legacy/umc8672.c
index 6e2c58c..ca79744 100644
--- a/drivers/ide/legacy/umc8672.c
+++ b/drivers/ide/legacy/umc8672.c
@@ -165,12 +165,21 @@
 	return 0;
 }
 
+int probe_umc8672 = 0;
+
+module_param_named(probe, probe_umc8672, bool, 0);
+MODULE_PARM_DESC(probe, "probe for UMC8672 chipset");
+
 /* Can be called directly from ide.c. */
 int __init umc8672_init(void)
 {
-	if (umc8672_probe())
-		return -ENODEV;
-	return 0;
+	if (probe_umc8672 == 0)
+		goto out;
+
+	if (umc8672_probe() == 0)
+		return 0;;
+out:
+	return -ENODEV;;
 }
 
 #ifdef MODULE