Add DT binding documentation for the Sophgo x8 EVB board [1].

Link: https://github.com/sophgo/sophgo-hardware/tree/master/SG2042/SG2042-x8-EVB [1]

Signed-off-by: Han Gao <rabenda.cn@gmail.com>
---
 Documentation/devicetree/bindings/riscv/sophgo.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/riscv/sophgo.yaml b/Documentation/devicetree/bindings/riscv/sophgo.yaml
index a14cb10ff3f0..ee244c9f75cc 100644
--- a/Documentation/devicetree/bindings/riscv/sophgo.yaml
+++ b/Documentation/devicetree/bindings/riscv/sophgo.yaml
@@ -34,6 +34,7 @@ properties:
       - items:
           - enum:
               - milkv,pioneer
+              - sophgo,sg2042-x8evb
           - const: sophgo,sg2042
 
 additionalProperties: true
-- 
2.47.2