Add initial support for Ingenic X1000 SoC and Y&A CU Neo board v5.

[Zhou Yanjie <zhouyanjie@xxxxxxxx>]

v4->v5:
1.Adjust item naming to prevent conflicts with subsequent "CU Geo" boards.
2.Rename "cu1000" to "cu1000-neo" to prevent conflicts with subsequent boards
  such as "cu1000-geo", and so on.
3.Remove "CONFIG_HZ=100" and "mem=32M@0x0" from defconfg, and update defconfig
  for msc controller and rtc.
4.Add msc controller and rtc DT node, and modify incorrect comments in DT.