Error:gvm-setup command not found

yocto_i.mx6_colibri$ gvm-setup
gvm-setup: command not found

This error i got when i am installing openvas

What are you trying to archive here ? Your prompt is imposing you run a Yocto on imx6, there is NO out of the box support for this. Please read how to compile the GVM stack and port this to a other platform.