dmi: Let dmi_walk() users pass private data

At the moment, dmi_walk() lacks flexibility, users can't pass data to
the callback function. Add a pointer for private data to make this
function more flexible.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/hwmon/fschmd.c b/drivers/hwmon/fschmd.c
index d07f4ef..b557f2e 100644
--- a/drivers/hwmon/fschmd.c
+++ b/drivers/hwmon/fschmd.c
@@ -856,7 +856,7 @@
 
 /* DMI decode routine to read voltage scaling factors from special DMI tables,
    which are available on FSC machines with an fscher or later chip. */
-static void fschmd_dmi_decode(const struct dmi_header *header)
+static void fschmd_dmi_decode(const struct dmi_header *header, void *dummy)
 {
 	int i, mult[3] = { 0 }, offset[3] = { 0 }, vref = 0, found = 0;
 
@@ -991,7 +991,7 @@
 
 	/* Read the special DMI table for fscher and newer chips */
 	if ((kind == fscher || kind >= fschrc) && dmi_vref == -1) {
-		dmi_walk(fschmd_dmi_decode);
+		dmi_walk(fschmd_dmi_decode, NULL);
 		if (dmi_vref == -1) {
 			dev_warn(&client->dev,
 				"Couldn't get voltage scaling factors from "