crypto: qat - leverage the GEN2 VF mask definiton

Replace hard coded VF masks in adf_gen2_pfvf.c with the recently
introduced ADF_GEN2_VF_MSK.

Signed-off-by: Marco Chiappero <marco.chiappero@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>