crypto: qat - add qat_6xxx driver

Add a new driver, qat_6xxx, to support QAT GEN6 devices.
QAT GEN6 devices are a follow-on generation of GEN4 devices and
differently from the previous generation, they can support all three
services (symmetric, asymmetric, and data compression) concurrently.

In order to have the qat_6xxx driver to reuse some of the GEN4 logic,
a new abstraction layer has been introduced to bridge the two
implementations. This allows to avoid code duplication and to keep the
qat_6xxx driver isolated from the GEN4 logic. This approach has been
used for the PF to VF logic and the HW CSR access logic.

Signed-off-by: Laurent M Coquerel <laurent.m.coquerel@intel.com>
Co-developed-by: George Abraham P <george.abraham.p@intel.com>
Signed-off-by: George Abraham P <george.abraham.p@intel.com>
Co-developed-by: Karthikeyan Gopal <karthikeyan.gopal@intel.com>
Signed-off-by: Karthikeyan Gopal <karthikeyan.gopal@intel.com>
Co-developed-by: Suman Kumar Chakraborty <suman.kumar.chakraborty@intel.com>
Signed-off-by: Suman Kumar Chakraborty <suman.kumar.chakraborty@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>