net: can: mscan: fix build breakage in mpc5xxx_can

Commit 74888760
"dt/net: Eliminate users of of_platform_{,un}register_driver"
broke building mscan driver. Fix it.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>