Add pfvf_ops structure to isolate PFVF related functions inside the
adf_hw_device_data structure.

For GEN2, the structure is populated using one of the two helper
functions, adf_gen2_init_pf_pfvf_ops() or adf_gen2_init_vf_pfvf_ops(),
for the PF and VF driver respectively.

For the DH895XCC PF driver, the structure is populated using
adf_gen2_init_pf_pfvf_ops() but some of the functions are then
overwritten.
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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>