net/can: convert drivers/net/can/* to use module_platform_driver()

This patch converts the drivers in drivers/net/can/* to use the
module_platform_driver() macro which makes the code smaller and a bit
simpler.

Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Bhupesh Sharma <bhupesh.sharma@st.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Kurt Van Dijck <kurt.van.dijck@eia.be>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>