crypto: qat - enable reporting of error counters for GEN6 devices

crypto: qat - enable reporting of error counters for GEN6 devices

Enable the reporting of error counters through sysfs for QAT GEN6
devices and update the ABI documentation.

This enables the reporting of the following:
   - errors_correctable - hardware correctable errors that allow the
     system to recover without data loss.
   - errors_nonfatal: errors that can be isolated to specific in-flight
     requests.
   - errors_fatal: errors that cannot be contained to a request,
     requiring a Function Level Reset (FLR) upon occurrence.

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>