mfd: mc13xxx-spi: Fix typo ("transfert")

That spelling is only correct in French :-)

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20221101165045.1017822-1-j.neuschaefer@gmx.net