can: mcp251xfd: mcp251xfd_register(): prepare to activate PLL after softreset

If the PLL is needed it must be switched on after chip reset. This
patch adds the required call to mcp251xfd_register().

Link: https://lore.kernel.org/all/20220207131047.282110-15-mkl@pengutronix.de


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