boards: v2: Add documentation index for converted boards

Adds documentation pages for rp2040-converted boards

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>

boards/index.rst

@@ -28,6 +28,10 @@ available under :zephyr_file:`doc/templates/board.tmpl`.
    xtensa/index.rst
    shields/index.rst
 
+   v2/adafruit/index.rst
    v2/arm/index.rst
    v2/gd/index.rst
+   v2/raspberry_pi/index.rst
    v2/renesas/index.rst
+   v2/sparkfun/index.rst
+   v2/wiznet/index.rst

boards/v2/adafruit/index.rst

@@ -0,0 +1,10 @@
+.. _boards-adafruit:
+
+Adafruit Industries LLC
+#######################
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

boards/v2/raspberry_pi/index.rst

@@ -0,0 +1,10 @@
+.. _boards-raspberry-pi:
+
+Raspberry Pi
+############
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

boards/v2/sparkfun/index.rst

@@ -0,0 +1,10 @@
+.. _boards-sparkfun-electronics:
+
+SparkFun Electronics
+####################
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

boards/v2/wiznet/index.rst

@@ -0,0 +1,10 @@
+.. _boards-wiznet:
+
+WIZnet
+######
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*