[PATCH 0/4] fix up pin definitions for BPI-R3 board

[Leith Bade]

This is my first patch submission to Linux so I apologise in advance for
any mistakes.

These changes were motivated by a pin conflict with the PCIe M.2 connector
and the push buttons. As a result I decided go work through all 100 GPIO
pins using the public board schematics. As I need to acquire a M.2 SSD to
test the PCIe pin change that patch is not included in this series yet.

Working though the pins I noticed a bug with with the MT7531 chip's reset
line which was on the wrong GPIO. Since it was conflicting with the boot
mode switch input GPIO pins I looked into ways to document the use of
those pins with the switch. I ended up choosing a gpio-hog, but please
let me know if there is a better alternative.

I also added some missing pin groups for some of the built-in SoC devices
to clearly document the use of those GPIO pins.

I have actually written up a gpio-line-names list give all the pins        
names to match their usage on this board. If there is interest in this     
I can submit this as an additional patch. I see only some MT8xxx devices   
in the mediatek directory have a gpio-line-names so I wasn't sure if I     
should add it.