crypto: qat - abstract arbiter access

The arbiter configuration, the offset to the arbiter config CSR and the
offset to the worker thread to service arbiter CSR are going to be
different in QAT GEN4 devices although the logic that uses them is the
same across all QAT generations.

This patch reworks the gen-specific parts of the arbiter access code by
introducing the arb_info structure, that contains the values that are
generation specific, and a function in the structure adf_hw_device_data,
get_arb_info(), that allows to get them.

Since the arbiter values for QAT GEN2 devices (c62x, c3xxx and
dh895xcc) are the same, a single function, adf_gen2_get_arb_info() is
provided in adf_gen2_hw_data.c and referenced by each QAT GEN2 driver.

Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Fiona Trahe <fiona.trahe@intel.com>
Reviewed-by: Wojciech Ziemba <wojciech.ziemba@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>