crypto: qat - enable VF irq after guest exits ungracefully

The VF bundle interrupt is not triggered any more in
the case when guest is shut down with sample app running.
Need to clear the flag interrupt bit when restarting to fix
this irrecoverable state.

Signed-off-by: Zeng Xin <xin.zeng@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>