pinctrl: ralink: rt2880: avoid double pointer to simplify code

Double pointer is being used and assigned in a bit dirty way to
assign functions in pinctrl. Instead of doing this just avoid it
and use directly 'p->func' instead.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20201213161721.6514-3-sergio.paracuellos@gmail.com


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