pinctrl: add a pincontrol driver for BCM6362

Add a pincotrol driver for BCM6362. BCM6362 allows muxing individual
GPIO pins to the LED controller, to be available by the integrated
wifi, or other functions. It also supports overlay groups, of which
only NAND is documented.

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/20210324081923.20379-14-noltari@gmail.com


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