Perform default mapping only for respective chips

The default memory mapping for the whole flash chip only makes sense
for chips that are directly connected to a bus serving memory cycles,
i.e. parallel, LPC and FWH chips. Use the new `.prepare_access` and
`.finish_access` hooks to map/unmap respective chips.

Going through the chip driver for this allows us to free the core
flashprog code from this peculiarity.

Change-Id: I54d1554b44b7e21fc18ef066103a9a26a2783b36
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/72521
4 files changed