The current implementation requires libvfscore to be selected. Without
libvfscore `read`, `write`, `close`, and `fstat` are undefined and
linking fails. With this commit we also fix a typo in the dependency
definition to libukalloc.
Signed-off-by: Simon Kuenzer <simon.kuenzer@neclab.eu> Reviewed-by: Sharan Santhanam <sharan.santhanam@neclab.eu>