There's no need to unset the drvdata on remove, so remove the unneeded call to
platform_set_drvdata() in m_can_plat_remove().

Link: https://lore.kernel.org/r/20201130133713.269256-6-mkl@pengutronix.deReviewed-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>