bindings: add grove header

Add bindind support for Grove header.

Signed-off-by: Joel Guittet <joelguittet@gmail.com>

dts/bindings/gpio/grove-header.yaml

@@ -0,0 +1,17 @@
+# Copyright (c) 2023 Joel Guittet
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+    GPIO pins exposing on Grove 4 pins headers.
+
+    This binding provides a nexus mapping for 2 pins as depicted below.
+
+        0  SCL/RXD/A/IN
+        1  SDA/TXD/B/OUT
+        -  VCC
+        -  GND
+
+
+compatible: "grove-header"
+
+include: [gpio-nexus.yaml, base.yaml]