dt-bindings: pinctrl: Fix file path for pinfunc include

Reference to pinfunc.h was wrong. Fix it.

Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
Link: https://lore.kernel.org/r/20221107071511.2764628-3-Mr.Bossman075@gmail.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>