arm64/mpam: fix a memleak in add_schema

openEuler inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I3BPPX


CVE: NA

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The default branch in switch will not run at present, but there may
be related extensions in the future, which may lead to memory leakage.

Signed-off-by: Zhang Ming <154842638@qq.com>
Reported-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Suggested-by: Jian Cheng <cj.chengjian@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>