crypto: qat - refactor fw config logic for 4xxx

The data structure adf_fw_config is used to select which firmware image
is loaded on a certain set of accelerator engines.
When support for 402xx was added, the adf_fw_config arrays were
duplicated in order to select different firmware images.

Since the configurations are the same regardless of the QAT GEN4
flavour, in preparation for adding support for multiple configurations,
refactor the logic that retrieves the firmware names in the 4xxx driver.
The structure adf_fw_config has been changed to contain a firmware object
id that is then mapped to a firmware name depending of the device type.

Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Adam Guerin <adam.guerin@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>