Merge tag 'rpi-next-2019.10' of https://github.com/mbgg/u-boot

- fix mailbox status register used for polling
- fix bcm2835_sdhost to wait long enough for a transfer to complete
- increase kernel image size from 8 MB to 64 MB on arm64
- add support for RPi4
- add prefixes for raspberry pi related stuff to git-mailrc