flashchips: Add ZD25D20

This adds another Zetta Device chip, the ZD25D20.

Change-Id: Idf805252647be44e28296a161d2e6160710bcc71
Signed-off-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-on: https://review.coreboot.org/23702
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed