Merge tag 'uniphier-v2020.10' of https://gitlab.denx.de/u-boot/custodians/u-boot-uniphier

UniPhier SoC updates for v2020.10

 - remove workaround for Cortex-A72

 - increase U-Boot proper size to 2MB

 - sync DT with Linux

 - add system bus controller driver

 - improve serial driver

 - add reset assertion to Denali NAND driver