can: flexcan: flexcan_open(): completely initialize controller before requesting IRQ

This patch changes the order in which the flexcan controller is brought up
during flexcan_open(). It makes sure that the chip is completely initialized
before the IRQs are requested and finally enabled.

Link: https://lore.kernel.org/r/20201119100917.3013281-5-mkl@pengutronix.de


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