can: peak_usb: remove unused/legacy peak_usb_netif_rx() function

Remove unused/legacy peak_usb_netif_rx() function (not longer used
since commit 28e0a70c ("can: peak_usb: CANFD: store 64-bits hw
timestamps").

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Link: https://lore.kernel.org/all/20230721180758.26199-1-ps.report@gmx.net


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>