crypto: qat - Fix invalid synchronization between register/unregister sym algs

The synchronization method used atomic was bogus.
Use a proper synchronization with mutex.

Cc: stable@vger.kernel.org
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>