I2C sw reset on STM32MP157

[jernejp21]

STM32MP157 doesn't have SWRST bit in I2C_CR1 register. Instead, you have to use PE bit to reset I2C.

[jernejp21]

From the manual:

PE must be kept low during at least three APB clock cycles in order to perform the software reset. This is ensured by writing the following software sequence:

1. Write PE = 0
2. Check PE = 0
3. Write PE = 1