sw64: fix the VDSO symbol generation for nm

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I56P0Z



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We were relying on GNU nm's ability to extract our VDSO symbols, but
newer nm will always display version strings after symbol names, which
cause so2s.sh to fail to generate vdso-syms.S. Fix so2s.sh to make it
work.

Besides, remove the copyright strings from so2s.sh.

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>