The error messages for the failure of dmaengine_prep_slave_sg are
not necessary, this patch removes all these pr_err, and returns with
the proper error code -EINVAL, not -1.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>