qualcommax: ipq60xx: add JDCloud RE-CS-07 support

qualcommax: ipq60xx: add JDCloud RE-CS-07 support

Specifications:
  SoC:     Qualcomm IPQ6010 1.8GHz
  RAM:     K4A8G165WC-BCTD x2 2GiB
  ETH:     QCA8075 (3x LAN, 1x WAN)
  Flash:   ICMAX 8GB eMMC
  Power:   DC 12V 2A
  USB:     1x 3.0
  Button:  Reset

Flash instructions:
  1. Download the initramfs image, rename it to
     initramfs.itb, host it with the tftp server.
  2. Enter "jdmt018R" to interrupt U-Boot
     when the following statement appears:
     "disabled console and autoboot in 2 seconds"
  3. Run these commands in U-Boot console:
     tftpboot initramfs.itb
     bootm
  4. After openwrt boots up, use scp or luci web
     to upload sysupgrade.bin to upgrade.

Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
Link: https://github.com/openwrt/openwrt/pull/19840
Signed-off-by: Robert Marko <robimarko@gmail.com>