net/ifc: do not notify before HW ready

net/ifc: do not notify before HW ready

If the device is not clearly reset by the previous driver and holds
some invalid ring addr, and the relay thread kicks it before HW is
properly re-configured, a bad DMA request may happen.

Besides, the notify_addr which is used by the relay thread is set in
the vdpa_ifcvf_start function, if a kick relay happens before
vdpa_ifcvf_start finishes, a null addr is accessed.

Fixes: a3f8150eac6d ("net/ifcvf: add ifcvf vDPA driver")
Cc: stable@dpdk.org
Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Reviewed-by: Xiaolong Ye <xiaolong.ye@intel.com>