* 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.
Moving the per-board clock configuration (which oscillators are available on the board, their frequencies, and which ones to use) as config options to the target database. This way, they're more easily overridable when third parties start creating boards with EFM32 MCUs
Aksel Skauge Mellbye
Christopher Haster
Steven Cooreman