crypto: qat - fix naming of PF/VF enable functions

Currently all the functions related to the activation of the PFVF
protocol, both on PF and VF, include the direction specific "vf2pf"
name.

Replace the existing naming schema with:
  - a direction agnostic naming, that applies to both PF and VF, for the
    function pointer ("pfvf")
  - a direction specific naming schema for the implementations ("pf2vf" or
    "vf2pf")

In particular this patch renames:
  - adf_pf_enable_vf2pf_comms() in adf_enable_pf2vf_comms()
  - enable_vf2pf_comms() in enable_pfvf_comms()

Signed-off-by: Marco Chiappero <marco.chiappero@intel.com>
Co-developed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-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>