feat(versal-net): add documentation for Versal NET SoC

Add description for Versal NET SoC.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Akshay Belsare <Akshay.Belsare@amd.com>
Change-Id: Idcbb893c6b9e46512308c53ba2a0bee48a022b0a
diff --git a/docs/plat/index.rst b/docs/plat/index.rst
index 1f497e0..28b1787 100644
--- a/docs/plat/index.rst
+++ b/docs/plat/index.rst
@@ -43,6 +43,7 @@
    synquacer
    stm32mp1
    ti-k3
+   xilinx-versal-net
    xilinx-versal
    xilinx-zynqmp
    brcm-stingray