Always enable the internal pull-up on the SCL line to always have a
functional I2C bus. This may increase power consumption where an
external pull up is present as well. But let's wait for a real world
use case where this would help to extend battery life before making
this configurable.
This fixes https://github.com/RIOT-OS/RIOT/issues/19021
This initial I2C support allows to use the I2C bus in controller mode to
interact with multiple peripherals in blocking mode. The CPU will
perform a busy wait when transferring data over I2C.
