can: usb: esd_usb2: esd_usb2_rx_event(): fix the interchange of the CAN RX and TX error counters

This patch fixes the interchanged fetch of the CAN RX and TX error
counters from the ESD_EV_CAN_ERROR_EXT message. The RX error counter
is really in struct rx_msg::data[2] and the TX error counter is in
struct rx_msg::data[3].

Fixes: 96d8e903

 ("can: Add driver for esd CAN-USB/2 device")
Link: https://lore.kernel.org/r/20210825215227.4947-2-stefan.maetje@esd.eu
Cc: stable@vger.kernel.org
Signed-off-by: Stefan Mätje <stefan.maetje@esd.eu>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>