crypto: qat - relocate PFVF VF related logic

Move device specific PFVF logic related to the VF to the newly created
adf_gen2_pfvf.c.
This refactory is done to isolate the GEN2 PFVF code into its own file
in preparation for the introduction of support for PFVF for GEN4
devices.

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