arm64: dts: Reserve memory regions for hi6220

On Hi6220, below memory regions in DDR have specific purpose:

  0x05e0,0000 - 0x05ef,ffff: For MCU firmware using at runtime;
  0x06df,f000 - 0x06df,ffff: For mailbox message data;
  0x0740,f000 - 0x0740,ffff: For MCU firmware's section;
  0x3e00,0000 - 0x3fff,ffff: For OP-TEE.

This patch reserves these memory regions in DT.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>