flashchips: add support for GigaDevice GD25WQ80E

Support GD25WQ80E, which is the internal flash of IT81202.

TEST=Building flashrom and flashing FW image into IT81202 successfully.

Change-Id: Ib5feaa6ecc7b11b2218e5f02c087b4331388bef8
Signed-off-by: Dino Li <Dino.Li@ite.com.tw>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/39820


Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>