crypto: qat - leverage bitfield.h utils for PFVF messages

The PFVF protocol defines messages composed of a number of control
bitfields. Replace all the code setting and retrieving such bits
with the utilities from bitfield.h, to improve code quality and
readability.

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