can: peak_usb: CANFD: store 64-bits hw timestamps

This patch allows to use the whole 64-bit timestamps received from the
CAN-FD device (expressed in µs) rather than only its low part, in the
hwtstamp structure of the skb transferred to the network layer, when a
CAN/CANFD frame has been received.

Link: https://lore.kernel.org/all/20210930094603.23134-1-s.grosjean@peak-system.com


Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>