crypto: qat - abstract PFVF messages with struct pfvf_message

This implementation of the PFVF protocol was designed around the GEN2
devices and its CSR format. In order to support future generations,
which come with differently sized fields, change the definition of the PFVF
message and make it abstract by means of a new pfvf_message struct. Also,
introduce some utilities to translate to and from the new message format
and the device specific CSR format.

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>