sw64: add basic support for sw64

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SPZD


CVE: NA

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This patch contains basic architecture support, including boot code,
devicetree support, memory management and DMA support, process and
signal management, time management, interrupt handling, syscalls,
clocks, loadable module support, ptrace support, headers and library
code.

Now, it works on SW3231 and SW831.

Signed-off-by: Gu Zitao <guzitao@wxiat.com> #openEuler_contributor
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>