Merge tag 'bugfixes-for-v2020.07-rc4' of https://gitlab.denx.de/u-boot/custodians/u-boot-i2c

i2c changes for v2020.07-rc4
- fix eeprom issue with AT24MAC402 (address != 0)
- fix in i2c-uclass.c when compiling compiling with -Wtype-limits
- designware_i2c: small fixes:
  - check if the device is powered
  - tidy up use of NULL priv