sw64: fix SPDX license identifier in uapi headers

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I56U83



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It used to fail to make headers_install. This patch adds
Linux-syscall-note to SPDX license to fix this issue.

Signed-off-by: Gu Zitao <guzitao@wxiat.com>

Signed-off-by: Gu Zitao <guzitao@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>