dediprog: Use default_spi_write_256

The default function already handles the chunking. However, we have
to account for command and address bytes in `.max_data_write` to make
use of it.

Change-Id: I738a3b8427f082f0144481b953a20f15d1813974
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/74863
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
1 file changed