can: mcp251xfd: mcp251xfd_chip_clock_enable(): simplify return

This patch simplifies the return of the mcp251xfd_chip_clock_enable()
function by direct returning the error.

Link: https://lore.kernel.org/r/20210128104644.2982125-8-mkl@pengutronix.de


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