CoQueue do not need to remove any element but the head of the list;
processing is always strictly FIFO. Therefore, the simpler singly-linked
QSIMPLEQ can be used instead.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>