Input: wacom - fix wacom_set_report retry logic

Logic sets a value and then reads it back to make sure it worked
and retries write on failures.  Since read and write share a buffer,
it needs to be set back up before writing though.

Issue is not seen a lot because 1) it doesn't need to retry for
a lot of tablets and 2) a lot of failures that need a retry are
from an -ETIMEDOUT and hopefully buffer is not touched in this case.

At least one user has shown logs with buffer being modified during
-ETIMEDOUT case with linux 3.7 kernel.
Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/tablet/wacom_sys.c

@@ -553,10 +553,10 @@ static int wacom_set_device_mode(struct usb_interface *intf, int report_id, int
 	if (!rep_data)
 		return error;
 
-	rep_data[0] = report_id;
-	rep_data[1] = mode;
-
 	do {
+		rep_data[0] = report_id;
+		rep_data[1] = mode;
+
 		error = wacom_set_report(intf, WAC_HID_FEATURE_REPORT,
 		                         report_id, rep_data, length, 1);
 		if (error >= 0)