staging: erofs: add trace points for reading zipped data

This patch adds trace points for reading zipped data.

Signed-off-by: Chen Gong <gongchen4@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>