crypto: qat - add support for decompression service to GEN6 devices

Add support to configure decompression as a separate service for QAT GEN6
devices. A new arbiter configuration has been added to map the hardware
decompression threads to all ring pairs.

The decompression service is enabled via sysfs by writing "decomp" to
"/sys/bus/pci/devices/<BDF>/qat/cfg_services".

The decompression service is not supported on QAT GEN2 and GEN4 devices,
and attempting it results in an invalid write error. The existing
compression service for QAT GEN2 and GEN4 devices remains unchanged and
supports both compression and decompression operations on the same ring
pair.

Co-developed-by: Karthikeyan Gopal <karthikeyan.gopal@intel.com>
Signed-off-by: Karthikeyan Gopal <karthikeyan.gopal@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>