can: c_can: Remove unused inline function

commit 524369e2 ("can: c_can: remove obsolete STRICT_FRAME_ORDERING Kconfig option")
left behind this, remove it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20200505084149.23848-1-yuehaibing@huawei.com


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