MFC r257200, r259121, r261410, r265853:

 - Remove #include <machine/frame.h>.
 - Add gpio parse routines according to sys/boot/fdt/dts/bindings-gpio.txt.
 - Follow r261352 by updating all drivers which are children of simplebus
   to check the status property in their probe routines.
 - Rename platform_gpio_init to be SoC specific, and make it static as it's
   only called from this file.

This is mostly catching up on some old MFCs that were done before this file
existed in the 10 branch.