crypto: qat - relocate PFVF disabled function

Move the function pfvf_comms_disabled() from the qat_4xxx module to
intel_qat as it will be used by other components to keep the PFVF
feature disabled.

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