You can remove the Oracle Virtual Networking host drivers in Oracle Solaris 11.3 OS by uninstalling them.
root@netra:~# pkg uninstall ovn-virtual-io
Packages to remove: 1
Create boot environment: Yes
Create backup boot environment: No
PHASE ITEMS
Removing old actions 32/32
Updating package state database Done
Updating package cache 1/1
Updating image state Done
Creating fast lookup database Done
Updating package cache 4/4
A clone of sol_83_2 exists and has been updated and activated.
On the next boot the Boot Environment sol_83_2-1 will be
mounted on '/'. Reboot when ready to switch to this updated BE.
Updating package cache 4/4
A new boot environment is created. After reboot the server will be booted into the new BE.
root@netra:~# svcs -a | grep ovn-virtual root@netra:~#