pinctrl: add a pincontrol driver for BCM6358

Add a pincotrol driver for BCM6358. BCM6358 allow overlaying different
functions onto the GPIO pins. It does not support configuring individual
pins but only whole groups. These groups may overlap, and still require
the directions to be set correctly in the GPIO register. In addition the
functions register controls other, not directly mux related functions.

Co-developed-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Link: https://lore.kernel.org/r/20210324081923.20379-11-noltari@gmail.com


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