doc: board: ti: introduce am62px documentation

Introduce basic documentation for the am62p family of SoCs.

Signed-off-by: Bryan Brattlof <bb@ti.com>
diff --git a/doc/board/ti/k3.rst b/doc/board/ti/k3.rst
index 15e1ed2..a1c01d1 100644
--- a/doc/board/ti/k3.rst
+++ b/doc/board/ti/k3.rst
@@ -35,6 +35,7 @@
    ../beagle/am62x_beagleplay
    ../phytec/phycore-am62x
    ../toradex/verdin-am62
+   am62px_sk
    am64x_evm
    am65x_evm
    j7200_evm