lfs: correct alignment restriction on lookahead buffer
lfs: correct alignment restriction on lookahead buffer

The buffer need only be 32-bit aligned.

Signed-off-by: Peter A. Bigot <650538893330be855f76604594b4820eb226769e@pabigot.com>

geky/littlefs,geky/littlefs,littlefs-project/littlefs,geky/littlefs,littlefs-project/littlefs,geky/littlefs