[PATCH v3] dt-bindings: gpio: cavium,thunder-8890: Remove DT binding

[Shi Hao <i.shihao.999@gmail.com>]

Remove the cavium,thunder-8890 GPIO binding as there are no active
use cases. A previous attempt was made to convert the binding to DT
schema, but since the binding is unused, remove it instead.

Signed-off-by: Shi Hao <i.shihao.999@gmail.com>
---
v3:
- Remove unused legacy text-based binding
- Drop previous DT schema conversion attempt

v2: https://lore.kernel.org/linux-devicetree/CAL_Jsq+0q8Wb==Xy_bi-j2D29BzZEN81tZr7VPGikL4AM5rbbQ@mail.gmail.com/T/#t
 - Rename schema file based on compatible string
 - Wrap commit message body as per kernel patch guidelines
 - Use appropriate maintainer name and email address in DT schema.
 - Change commit subject as per guidelines
 - Fix $id path

Note:
* This patch is part of the GSoC2026 application process for device tree bindings conversions
* https://github.com/LinuxFoundationGSoC/ProjectIdeas/wiki/GSoC-2026-Device-Tree-Bindings
---
 .../bindings/gpio/gpio-thunderx.txt           | 27 -------------------
 1 file changed, 27 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/gpio/gpio-thunderx.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio-thunderx.txt b/Documentation/devicetree/bindings/gpio/gpio-thunderx.txt
deleted file mode 100644
index 3f883ae29d11..000000000000
--- a/Documentation/devicetree/bindings/gpio/gpio-thunderx.txt
+++ /dev/null
@@ -1,27 +0,0 @@
-Cavium ThunderX/OCTEON-TX GPIO controller bindings
-
-Required Properties:
-- reg: The controller bus address.
-- gpio-controller: Marks the device node as a GPIO controller.
-- #gpio-cells: Must be 2.
-  - First cell is the GPIO pin number relative to the controller.
-  - Second cell is a standard generic flag bitfield as described in gpio.txt.
-
-Optional Properties:
-- compatible: "cavium,thunder-8890-gpio", unused as PCI driver binding is used.
-- interrupt-controller: Marks the device node as an interrupt controller.
-- #interrupt-cells: Must be present and have value of 2 if
-                    "interrupt-controller" is present.
-  - First cell is the GPIO pin number relative to the controller.
-  - Second cell is triggering flags as defined in interrupts.txt.
-
-Example:
-
-gpio_6_0: gpio@6,0 {
-	compatible = "cavium,thunder-8890-gpio";
-	reg = <0x3000 0 0 0 0>; /*  DEVFN = 0x30 (6:0) */
-	gpio-controller;
-	#gpio-cells = <2>;
-	interrupt-controller;
-	#interrupt-cells = <2>;
-};
-- 
2.53.0