According to the reference manual, you can mux the PWM output on GPIO27
and GPIO51. This was missing in the pinmux table. Add it.

Tested on a LAN9668 on GPIO51.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220326192848.2944519-1-michael@walle.ccSigned-off-by: Linus Walleij <linus.walleij@linaro.org>