crypto: qat - Set max request size

The device doensn't support the default value and will change it to 256, which
will cause performace degradation for biger packets.
Add an explicit write to set it to 1024.

Reported-by: Tianliang Wang <tianliang.wang@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>