A firmware update for QAT GEN2 changed the format of a data
structure used to report the heartbeat counters.

To support all firmware versions, extend the heartbeat logic
with an algorithm that detects the number of counters returned
by firmware. The algorithm detects the number of counters to
be used (and size of the corresponding data structure) by the
comparison the expected size of the data in memory, with the data
which was written by the firmware.

Firmware detection is done one time during the first read of heartbeat
debugfs file to avoid increasing the time needed to load the module.
Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>