ft2232_spi.c: change the chunksize from 256 to 270

This is to really make use of page write time advantage.
Because the Chunksize must be 256Byte raw data plus the address and cmd bytes.

For details check:
https://mail.coreboot.org/hyperkitty/list/flashrom@flashrom.org/message/W2HULJTDPHWPBZY6MLM6TGT7RTHSGHON/

Signed-off-by: Simon Buhrow <simon.buhrow@posteo.de>
Change-Id: Iac067a23025e9df053ab9cd4e82a98de70046c18
Reviewed-on: https://review.coreboot.org/c/flashrom/+/39632
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
1 file changed