Merge tag 'for-v2020.10' of https://gitlab.denx.de/u-boot/custodians/u-boot-i2c

i2c changes for v2020.10
- Add support for I2C controllers found on Octeon II/III and Octeon TX
  TX2 SoC platforms.
- Add I2C controller support for Cortina Access CAxxxx SoCs
- new rtc methods, rtc command, and tests
- imx_lpi2c: Improve the codes to use private data
- stm32f7_i2c.c: Add new compatible "st,stm32mp15-i2c"
- stm32f7_i2c.c: Add Fast Mode Plus support
- pwm: Add PWM driver for SiFive SoC