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/dtc2278.c b/drivers/ide/legacy/dtc2278.c
index f2903b6..0219ffa 100644
--- a/drivers/ide/legacy/dtc2278.c
+++ b/drivers/ide/legacy/dtc2278.c
@@ -92,7 +92,7 @@
 	HWIF(drive)->drives[!drive->select.b.unit].io_32bit = 1;
 }
 
-static int __init probe_dtc2278(void)
+static int __init dtc2278_probe(void)
 {
 	unsigned long flags;
 	ide_hwif_t *hwif, *mate;
@@ -143,10 +143,18 @@
 	return 0;
 }
 
+int probe_dtc2278 = 0;
+
+module_param_named(probe, probe_dtc2278, bool, 0);
+MODULE_PARM_DESC(probe, "probe for DTC2278xx chipsets");
+
 /* Can be called directly from ide.c. */
 int __init dtc2278_init(void)
 {
-	if (probe_dtc2278()) {
+	if (probe_dtc2278 == 0)
+		return -ENODEV;
+
+	if (dtc2278_probe()) {
 		printk(KERN_ERR "dtc2278: ide interfaces already in use!\n");
 		return -EBUSY;
 	}