staging: erofs: remove redundant likely/unlikely annotation in namei.c

unlikely has already included in IS_ERR(),
so just remove redundant likely/unlikely
annotation.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>