Merge patch series "Add DFU and usb boot for TI am62x SK and beagleplay"

Martyn Welch <martyn.welch@collabora.com> says:

This series adds DFU support for TI AM62 SK and beagleplay boards.

I have picked this series up from Sjoerd due to time constraints.

Since the last revision:
* Removed dwc3 mode setting in favour of reinstating forced peripheral
  mode for usb0
* Use of config fragments for both r5 and a53 DFU configuration to
  reduce duplication
* Typographical improvements to documentation

We plan to also submit the dts changes to linux so that those can be
dropped again in the near future (hopefully)