kernel: fix alexkar* kernel crashes due to missing case in switch.

Fixes https://github.com/veox/sgminer/issues/27

driver-opencl.c

@@ -1256,13 +1256,14 @@ static bool opencl_thread_init(struct thr_info *thr)
 	}
 
 	switch (clState->chosen_kernel) {
+	case KL_ALEXKARNEW:
+	case KL_ALEXKAROLD:
 	case KL_CKOLIVAS:
-			thrdata->queue_kernel_parameters = &queue_scrypt_kernel;
-			break;
 	case KL_ZUIKKIS:
 		thrdata->queue_kernel_parameters = &queue_scrypt_kernel;
 		break;
 	default:
+		applog(LOG_ERR, "Failed to choose kernel in opencl_thread_init");
 		break;
 	}