pinctrl: bcm2835: Change init order for gpio hogs

pinctrl-bcm2835 is a combined pinctrl/gpio driver. Currently the gpio
side is registered first, but this breaks gpio hogs (which are
configured during gpiochip_add_data). Part of the hog initialisation
is a call to pinctrl_gpio_request, and since the pinctrl driver hasn't
yet been registered this results in an -EPROBE_DEFER from which it can
never recover.

Change the initialisation sequence to register the pinctrl driver
first.

See: https://www.raspberrypi.org/forums/viewtopic.php?f=107&t=260600



Signed-off-by: Phil Elwell <phil@raspberrypi.org>