Merge tag 'xilinx-for-v2021.07-rc2' of https://source.denx.de/u-boot/custodians/u-boot-microblaze

Xilinx changes for v2021.07-rc2

xilinx:
- Enable saving variables based on bootmode
- Cleanup usb dfu setup and wire it up with usb bootmode
- Fix bootscript address logic
- Remove GD references (spi, Versal)
- Enable capsule update

clk:
- Small Kconfig fix

net:
- Fix gmii2rgmii bridge binding

usb:
- Propagate error (dfu gadget)