Since most of the code in i2c_api.c is now relying on STM32 HAL, there
is now a possibility to make a common usage of this code accross families.
The IP version definition is introduced per family, to allow a switch of
functionnalities, especially the frequency management which differs.
BTw, we fix the F0 frequency settings at the same time.
F1 is managed for now as an exception as the HAL API for sequential transmit
/receive is not yet available (coming soon)
Laurent MEUNIER