There's a closed pull request on the void-packages repository

virtualbox-ose-dkms: linux5.6 patch
https://github.com/void-linux/void-packages/pull/20581

Description:
PR with the patches mentioned in #20576

https://www.virtualbox.org/changeset/83471/vbox
https://www.virtualbox.org/changeset/83473/vbox
https://www.virtualbox.org/changeset/83484/vbox