* MCUs within a family like EFM32GG can omit some peripherals, e.g. EFM32GG230 doesn't have UART
* This commit adds a check to make them compilable, relevant mainly for custom boards
* Update i2c driver to tackle multiple I2C object instances on different pins
* Update pinmap to enable the extra peripherals of EFx32xG12 over EFx32xG1