doc: board: ti: Add J722S-EVM documentation

Introduce basic documentation for the J722S-EVM.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
diff --git a/doc/board/ti/k3.rst b/doc/board/ti/k3.rst
index a1c01d1..eba0f0e 100644
--- a/doc/board/ti/k3.rst
+++ b/doc/board/ti/k3.rst
@@ -42,6 +42,7 @@
    ../beagle/j721e_beagleboneai64
    j721e_evm
    j721s2_evm
+   j722s_evm
    j784s4_evm
 
 Boot Flow Overview