can: m_can: m_can_class_unregister(): move right after m_can_class_register()

This patch moves the function m_can_class_unregister() directly after the
m_can_class_register() function.

Link: https://lore.kernel.org/r/20201130133713.269256-7-mkl@pengutronix.de


Reviewed-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>