Merge tag 'rpi-next-2020.04' of https://gitlab.denx.de/u-boot/custodians/u-boot-raspberrypi

- DFU support file operations lager then the default max size
- add dfu support to dwc2 for bcm2835
- enable DFU for RPi4
- Fix RPi4 memory map to include the genet device
- add driver for the genet ethernet device
- enable network support in RPi4 config