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>

drivers/ide/legacy/qd65xx.c

@@ -488,9 +488,17 @@ static int __init qd_probe(int base)
 	return 1;
 }
 
+int probe_qd65xx = 0;
+
+module_param_named(probe, probe_qd65xx, bool, 0);
+MODULE_PARM_DESC(probe, "probe for QD65xx chipsets");
+
 /* Can be called directly from ide.c. */
 int __init qd65xx_init(void)
 {
+	if (probe_qd65xx == 0)
+		return -ENODEV;
+
 	if (qd_probe(0x30))
 		qd_probe(0xb0);
 	if (ide_hwifs[0].chipset != ide_qd65xx &&