Kernel 6.2 folded virqfd (eventd interface for VFIO interrupts)
into the base vfio module, it is no longer a tristate option.
Change suggested by vincejv on GitHub:
https://github.com/openwrt/openwrt/pull/14868#issuecomment-1998260124
Signed-off-by: Mathew McBride <matt@traverse.com.au>