Samsung DTS ARM changes for v5.20

1. Add display panel and backlight to P4 Note family (Samsung Galaxy
   Note 10.1).
2. DTS cleanup: white-spaces, node names, LED color/function.
3. Switch to DTS-local header for pinctrl register values instead of
   bindings header.  The bindings header is being deprecated because it
   does not reflect the purpose of bindings.