dts/core: Use own fragments to modify existing pinmuxes [REVPI-2293]

Created by: iluminat23

If we redefine muxes which are already defined in the devicetree we might get errors when loading the overlay at runtime. There is no usefull error message. It just says the loding of the overlay faild. The bootloader seems not so picky and loads the overlay.

We move each pinmux which is already defined in bcm2708-rpi-cm.dts, bcm2710-rpi-cm3.dts or bcm2711-rpi-cm4s.dts, to its own fragment. And we modify the already defined pinmux instead of creating a new one.

Signed-off-by: Philipp Rosenberger p.rosenberger@kunbus.com