Introduce SMP support for CI20 (based on JZ4780) v4.

Subject: Introduce SMP support for CI20 (based on JZ4780) v4.
From: 周琰杰 (Zhou Yanjie) <zhouyanjie@xxxxxxxxxxxxxx>
Date: Sat, 15 Feb 2020 02:02:33 +0800
Cc: linux-clk@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, devicetree@xxxxxxxxxxxxxxx, paul@xxxxxxxxxxxxxxx, mturquette@xxxxxxxxxxxx, sboyd@xxxxxxxxxx, robh+dt@xxxxxxxxxx, mark.rutland@xxxxxxx, ralf@xxxxxxxxxxxxxx, paulburton@xxxxxxxxxx, jiaxun.yang@xxxxxxxxxxx, chenhc@xxxxxxxxxx, allison@xxxxxxxxxxx, tglx@xxxxxxxxxxxxx, daniel.lezcano@xxxxxxxxxx, geert+renesas@xxxxxxxxx, krzk@xxxxxxxxxx, keescook@xxxxxxxxxxxx, ebiederm@xxxxxxxxxxxx, miquel.raynal@xxxxxxxxxxx, paul@xxxxxxxxxxxxx, hns@xxxxxxxxxxxxx, sernia.zhou@xxxxxxxxxxx, zhenwenjin@xxxxxxxxx, mips-creator-ci20-dev@xxxxxxxxxxxxxxxx, 1326991897@xxxxxx

Introduce SMP support for MIPS Creator CI20, which is
based on Ingenic JZ4780 SoC.

Follow-Ups:
- [PATCH v4 2/6] clocksource: Ingenic: Add high resolution timer support for SMP.
  - From: 周琰杰 (Zhou Yanjie)
- [PATCH v4 6/6] MIPS: CI20: Update defconfig to support SMP.
  - From: 周琰杰 (Zhou Yanjie)
- [PATCH v4 0/6] Introduce SMP support for JZ4780.
  - From: 周琰杰 (Zhou Yanjie)
- [PATCH v4 3/6] dt-bindings: MIPS: Document Ingenic SoCs binding.
  - From: 周琰杰 (Zhou Yanjie)
- [PATCH v4 4/6] MIPS: Ingenic: Add 'cpus' node for Ingenic SoCs.
  - From: 周琰杰 (Zhou Yanjie)
- [PATCH v4 1/6] MIPS: JZ4780: Introduce SMP support.
  - From: 周琰杰 (Zhou Yanjie)
- [PATCH v4 5/6] MIPS: CI20: Modify DTS to support high resolution timer for SMP.
  - From: 周琰杰 (Zhou Yanjie)