crypto: qat - interrupts need to be enabled when VFs are disabled

IRQs need to be enabled when VFs go down in case some VF to PF
comms happens.

Tested-by: Suman Bangalore Sathyanarayana <sumanx.bangalore.sathyanarayana@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>