sw64: remove unnecessary parameter in REG_OFFSET_NAME

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I56OLG



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The `reg` and `r` are always the same, so save one of them and
remove the other.

Signed-off-by: He Chuyue <hechuyue@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>