xhci: Fix a logic issue when display Zhaoxin XHCI root hub speed

zhaoxin inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I40QDN


CVE: NA

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Fix a logic issue when display Zhaoxin XHCI root hub speed.

Signed-off-by: LeoLiu-oc <LeoLiu-oc@zhaoxin.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>