arm64: dts: ti: j721e-som/common-proc-board: Add product links

Add product links to get reference to schematics and design files

Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20230601183151.1000157-4-nm@ti.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>