linux_spi: Use default_spi_read()/_write_256()

The default functions already handle the chunking.

Change-Id: I6ed90c3eed3a3e36a560c5036704cf5ebc26f96e
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/74862
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
1 file changed