crypto: qat - remove hardcoded bank irq clear flag mask

Replace hardcoded value of the bank interrupt clear flag mask with a
value calculated on the fly which is based on the number of rings
present in a bank. This is to support devices that have a number of
rings per bank different than 16.

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