stm32f0, l3, l4 are currently sharing the same duplicated header, and
stm32l0 uses the same peripheral. Stop copy-pasting stuff and centralize
definitions into a iwdg_common_v2.h header.
to remove variations, redundancies, add missing, fix errors. All c files
refer only to the dispatch style headers in /include/stm32. Those headers
#include memorymap.h and cm3/common.h. All references to
these are removed from the family specific headers. Ethernet untouched as
it appears incomplete.
Added dummy spi.c for F0/F3. Fix some doxygen anomalies.
