[PATCH] Add GigaDevice GD25QXX Series Support

[Justin Chevrier]

Attached is a patch to add GigaDevice's GD25QXX series of chips.  I
ran across the GD25Q80 variant in a promotional greeting card. I
successfully read, erased and wrote to this particular chip [1]. I
added various other GigaDevice chips that I found on their website and
marked them as untested. Of note is that in particular the GD25Q80
chip has two versions the base variant (that I have) and a 'B'
variant. The apparent difference is that the 'B' variant has support
for OTP regions, while the plain one does not. I believe they present
the same identifier when queried, not sure what issues this poses,
leaving in OTP did not impact the operation of my particular non 'B'
variant chip. Here is a link to the root page containing datasheets
for these chips:

http://www.gigadevice.com/Product/SPI.php?WebPageTypeId=98&WebPageTypeId...

Justin

Signed-off-by: Justin Chevrier

[1]

./flashrom -p rayer_spi -w new.rom
flashrom v0.9.5.2-r1517 on Linux 3.2.1-gentoo-r2 (x86_64), built with
libpci 3.1.9, GCC 4.5.3, little endian
flashrom is free software, get the source code at http://www.flashrom.org

Calibrating delay loop... delay loop is unreliable, trying to continue OK.
Found Gigadevice flash chip "GD25Q80" (1024 kB, SPI) on rayer_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... VERIFIED.