l4 is pages, not sectors, so update apis to be consistent. (other
families use page/sector as defined in the reference manual)
Make sure that pages on the second bank can also be erased. Use the
same style in use for f2/4/7 for sector numbers across banks.
All the "f" type flash parts have an EOP flag, even if it's in different
bit positions. Add a header for this common functionality, and move
it's implementation to the existing common file.
Turns out, there's lots of common code for flash. Pull up prefetch
on/off to start with, as there's only a single bit name different.
Pull up the definitions of common API functions too, starting with
flash_set_ws. Even if the implementations are different, things that
meant to be the same, should be defined centrally.
Karl Palsson