QAT devices implement a mechanism that allows them to go autonomously
to a low power state depending on the load.

Expose power management info by providing the "pm_status" file under
debugfs. This includes PM state, PM event log, PM event counters, PM HW
CSRs, per-resource type constrain counters and per-domain power gating
status specific to the QAT device.

This information is retrieved from (1) the FW by means of
ICP_QAT_FW_PM_INFO command, (2) CSRs and (3) counters collected by the
device driver.

In addition, add logic to keep track and report power management event
interrupts and acks/nacks sent to FW to allow/prevent state transitions.
Signed-off-by: Lucas Segarra Fernandez <lucas.segarra.fernandez@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>