ath6kl: return error block size is not power of 2

Currently only a warning is emitted but no error is returned.
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath6kl/htc_hif.c

@@ -621,6 +621,7 @@ int ath6kldev_setup(struct ath6kl_device *dev)
 	/* must be a power of 2 */
 	if ((dev->htc_cnxt->block_sz & (dev->htc_cnxt->block_sz - 1)) != 0) {
 		WARN_ON(1);
+		status = -EINVAL;
 		goto fail_setup;
 	}