can: mcp251xfd: move netdevice.h to mcp251xfd.h

The netdevice.h header is needed in mcp251xfd.h, so that it can be
included without further headers.

Link: https://lore.kernel.org/r/20210304160328.2752293-4-mkl@pengutronix.de


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