C2C reset passed to the CPCIS I2C bus

In context of deprecation of DI/OT FMC Carrier v1 (be-cem-edl/diot/fmc-carrier#26), the C2C reset I2C line can be moved to a shared I2C bus, reducing the platform's resource use (see be-cem-edl/diot/fmc-carrier#23).

This MR:

• Makes the reset now performed be from a PS I2C line connected to a shared I2C bus
• SHARED_BUS lines becomes unused so they were liberated again

Should be merged at the same time as:

• be-cem-edl/diot/fmc-carrier!39
• https://gitlab.cern.ch/be-cem-edl/diot/python-diot/-/merge_requests/9

Should only be merged when be-cem-edl/diot/fmc-carrier#26 is closed.

Closes #158 (closed)