generic/config-6.12: add new option

generic/config-6.12: add new option

Add new option required to build with VHOST_MENU=y

This option enables two IOCTLs: VHOST_SET_FORK_FROM_OWNER and
VHOST_GET_FORK_FROM_OWNER. These allow userspace applications
to modify the vhost worker mode for vhost devices.

Also expose module parameter 'fork_from_owner_default' to allow users
to configure the default mode for vhost workers.

By default, `VHOST_ENABLE_FORK_OWNER_CONTROL` is set to `y`,
users can change the worker thread mode as needed.
If this config is disabled (n),the related IOCTLs and parameters will
be unavailable.

If unsure, say "Y".

Signed-off-by: John Audia <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/19618
Signed-off-by: Robert Marko <[email protected]>