HID: plantronics: Workaround for double volume key presses

Plantronics Blackwire 3220 Series (047f:c056) sends HID reports twice
for each volume key press. This patch adds a quirk to hid-plantronics
for this product ID, which will ignore the second volume key press if
it happens within 5 ms from the last one that was handled.

The patch was tested on the mentioned model only, it shouldn't affect
other models, however, this quirk might be needed for them too.
Auto-repeat (when a key is held pressed) is not affected, because the
rate is about 3 times per second, which is far less frequent than once
in 5 ms.

Fixes: 81bb773faed7 ("HID: plantronics: Update to map volume up/down controls")
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index e42aaae..4c74d87 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -944,6 +944,7 @@
 #define USB_DEVICE_ID_ORTEK_IHOME_IMAC_A210S	0x8003
 
 #define USB_VENDOR_ID_PLANTRONICS	0x047f
+#define USB_DEVICE_ID_PLANTRONICS_BLACKWIRE_3220_SERIES	0xc056
 
 #define USB_VENDOR_ID_PANASONIC		0x04da
 #define USB_DEVICE_ID_PANABOARD_UBT780	0x1044