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
This was also fixed in ac29b654a992a4855626fc0b92874d3847914f85 in a
different way. I think the mask definition should be left with 1s
indicating the bits of interest.
See also 87ea496ca768d18e51d8654cbad9cb261a881b1b.
This reverts commit 2433f17e7341d6afcda24d395d0b93c50a37b7b1.