(prevents inclusion and also issues warning)
Changes to some source files to remove references to common headers.
Changes to rng.h to make guard symbols the same in f2 and f4.
to remove errors, duplications and inconsistencies.
File lib/stm32/f1/pwr.c - all code removed as it duplicates that in common/pwr_common.c
Remaining changes do not affect code. Compiles OK.
TODO efm32 has no code so generates no modules
TODO F2 needs pwr.c
TODO L1 needs dma.h and dma.c
IDR represents the level on pin input while ODR is the value requested by the
programmer. This makes a difference for example when using the output as open
drain.
