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
Code added for L1 to support the PWR Control block didn't properly
follow the HACKING_COMMON_DOC guidelines. The naming was wrong, and
some headers were missing. This commit has no functional changes, it
only addresses the style and structure problems.