[stm32] Use correct offsets for UniqueID bits

STM32L1 has a different set of offsets, not just a different base
address, so we can't have common registers definitions.  Also, out of
F0,F1,F2,F3,F4,L1, only the F1 has the odd note about 2x16bit registers
and 2x32bit registers with one 16bit register marked as "This field
value is also reserved for a future feature."  Therefore, replace the
awkward reading out as multiple words and just copy them in.

F2 and F4 were missing definitions altogether.