Repair to documentation (most documented files)

to remove errors, duplications and inconsistencies.

Sorry its a biggish one but the only code affected is:

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