can: pcan_usb: fix wrong memcpy() bytes length

Fix possibly wrong memcpy() bytes length since some CAN records received from
PCAN-USB could define a DLC field in range [9..15].
In that case, the real DLC value MUST be used to move forward the record pointer
but, only 8 bytes max. MUST be copied into the data field of the struct
can_frame object of the skb given to the network core.

Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/can/usb/peak_usb/pcan_usb.c

@@ -649,7 +649,7 @@ static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len)
 		if ((mc->ptr + rec_len) > mc->end)
 			goto decode_failed;
 
-		memcpy(cf->data, mc->ptr, rec_len);
+		memcpy(cf->data, mc->ptr, cf->can_dlc);
 		mc->ptr += rec_len;
 	}