board: toradex: add Toradex SMARC iMX8MP

Add support for the Toradex SMARC iMX8MP.

Link: https://www.toradex.com/computer-on-modules/smarc-arm-family/nxp-imx-8m-plus
Link: https://www.toradex.com/products/carrier-board/smarc-development-board-kit
Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
diff --git a/doc/board/toradex/index.rst b/doc/board/toradex/index.rst
index 89fbdcb..7d510a8 100644
--- a/doc/board/toradex/index.rst
+++ b/doc/board/toradex/index.rst
@@ -9,6 +9,7 @@
    apalis-imx8
    colibri_imx7
    colibri-imx8x
+   smarc-imx8mp
    verdin-am62
    verdin-imx8mm
    verdin-imx8mp