flashchips: Add GigaDevice GD25LQ20, update family up to GD25LQ16

They all are supposed to support volatile status-register writes and
feature the most usual block-protection bits. The 1.695V limit looks
certainly like a typo. All datasheets found start at 1.65V.

Datasheets used:
https://device.report/m/0dd9581d418568153f88153cd3bd298f85f83fba817fc6b242405e98002f7c44.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20220714/DS-00347-GD25LQ20C-Rev1.5.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20221129/DS-00785-GD25LQ20E-Rev1.2.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20221129/DS-00663-GD25LQ40E-Rev1.2.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20220714/DS-00405-GD25LQ80C-Rev1.9.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20220714/DS-00583-GD25LQ80E-Rev1.3.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20220714/DS-00289-GD25LQ16C-Rev2.1.pdf
https://www.gigadevice.com.cn/Public/Uploads/uploadfile/files/20240902/DS-00576-GD25LQ16E-Rev1.4.pdf

Change-Id: I23b3b199d9c6fd7b42de468cbe8b3945774f15e8
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/301
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/include/flashchips.h b/include/flashchips.h
index 301f579..e901069 100644
--- a/include/flashchips.h
+++ b/include/flashchips.h
@@ -408,6 +408,7 @@
 #define GIGADEVICE_GD25B512ME	0x471a	/* Same as GD25R512ME */
 #define GIGADEVICE_GD55B01GE	0x471b
 #define GIGADEVICE_GD55B02GE	0x471c
+#define GIGADEVICE_GD25LQ20	0x6012
 #define GIGADEVICE_GD25LQ40	0x6013
 #define GIGADEVICE_GD25LQ80	0x6014
 #define GIGADEVICE_GD25LQ16	0x6015