Previously, all these were located in stm32f2.h. As for me, that
was better: these definitions are really CPU-specific (describe
the CPU specific registers and their fields), and have no rela-
tion to driver or anything else c-code; latters just use them. So,
my opinion is that their place in stm32f2.h header, not in c-files.

The only positive thing here: is more clear stm32f2.h file.

Note, the definitions used by several files (e.g. RCC regs base, used
by clock.c and stm32f2_serial.c) I kept in stm32f2.h. The same about
C-types of register maps.

Signed-off-by: Yuri Tikhonov <yur@emcraft.com>