HID: Do not discard truncated input reports

Truncated reports should not be discarded since it prevents buggy
devices from communicating with userspace.

Prior to the regession introduced in 2.6.20, a shorter-than-expected
report in hid_input_report() was passed thru after having the missing
bytes cleared. This behavior was established over a few patches in the
2.6.early-teens days, including commit
cd610457.

This patch restores the previous behavior and fixes the regression.
Signed-off-by: NAdam Kropelin <akropel1@rochester.rr.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/hid-core.c

@@ -969,7 +969,7 @@ int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int i
 
 	if (size < rsize) {
 		dbg("report %d is too short, (%d < %d)", report->id, size, rsize);
-		return -1;
+		memset(data + size, 0, rsize - size);
 	}
 
 	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)