Merge patch series "fw_env: cleanup flash_write_buf()"

Rafał Miłecki <rafal@milecki.pl> says:

I found flash_write_buf() somehow more difficult to follow than needed.
Some code turned out to be inconsistent and some not really needed.

There is a set of 6 patches that should be small enough to make them easy
to review. I was wondering if I should squash patches 5 and 6 but ended up
with sending two smaller diffs.

Those changes shouldn't really change any behaviour (except for smaller mem
alloc). Let me know if there are any issues with this!

Link: https://lore.kernel.org/r/20260221100011.29049-1-zajec5@gmail.com