can: mcba_usb: mcba_usb_start_xmit(): first fill skb, then pass to can_put_echo_skb()

The driver has to first fill the skb with data and then handle it to
can_put_echo_skb(). This patch moves the can_put_echo_skb() down, right before
sending the skb out via USB.

Fixes: 51f3baad ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Cc: Remigiusz Kołłątaj <remigiusz.kollataj@mobica.com>
Link: https://lore.kernel.org/r/20201111221204.1639007-1-mkl@pengutronix.de


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