sw64: fix the number of aux entries in ARCH_DLINFO

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I56UNZ



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There's only AT_SYSINFO_EHDR auxiliary vector so far in SW64 ELF.
It's used to store vdso base of current task.

Signed-off-by: He Sheng <hesheng@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>