tcp_comp: Fix comp_read_size return value

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I47SV5?from=project-issue


CVE: NA

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In comp_read_size rxm->offset should be subtracted from skb->len. And use
strp_done to release resoureces when destroy sock.

Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Lu Wei <luwei32@huawei.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>