* Using PinName as bitfield doesn't work without warnings, since NC
needs all 32 bits to be represented.
* lp_ticker should not be freed when interrupt is disabled, since this
will kill the timebase.
* Update i2c driver to tackle multiple I2C object instances on different pins
* Update pinmap to enable the extra peripherals of EFx32xG12 over EFx32xG1
First wave of squashing header files in order to get to a more sensible folder tree.
* Moved header files with 100% similarity to common folder
* Created a CommonPinNames.h header containing the base pin names P[A-F][0-15] and NC