Hi @chalu,
Instead of trying to compile it yourself, this overlay should be included with your image on our latest nightly build. I believe it’s easier to download one of these images and test it out of the box. Please check this thread for more information on which image to download: Support of rpmsg in TorizonCore on Verdin iMX8MP - #15 by vix. Also, check my last answer there, it will be necessary to configure u-boot properly.
The images (including the nightly builds) you can find them here: Toradex Download Links (Torizon, Yocto Project Reference Images, WinCE and Partner Demos) | Toradex Developer Center
Best Regards,
Hiago.