ipq806x: Add support for IPQ8064 AP161 board

ipq806x: Add support for IPQ8064 AP161 board

Specification:
   - SoC: Qualcomm Atheros IPQ8064 ARM-v7 Dual Core SMP CPU
   - RAM: 512MB DDR3 System Memory
   - NOR Flash: 32MB SPI NOR
   - NAND Flash: 256MB NAND
   - Ethernet: 5 x 1G via QCA8337N
   - USB: 2 x USB 3.0 SuperSpeed
   - PCIe: 3x Mini PCIe 2.0 Slots
	   Three PCIE2.0 connectors can connect two or three radio cards
           such as the CUS260 for 2.4 GHz WLAN and the CUS239 for 802.11ac WLAN

 How to flash via u-boot console:
   tftpboot 0x44000000 openwrt-ipq806x-qcom_ipq8064-ap161-squashfs-nand-factory.bin
   nand erase  0x1340000 0x4000000
   nand write  0x44000000 0x1340000 $filesize
   setenv bootargs ‘console=ttyMSM0,115200 ubi.mtd=ubi root=/dev/ubiblock0_1’
   saveenv
   bootm

 Further upgrades via sysupgrade.

 Tested on IPQ8064 AP161 Board:
   1) NAND boot
   2) Tested USB and PCIe interfaces
   3) WDOG test
   4) cpu frequency scaling
   5) ethernet, 2G and 5G WiFi
   6) ubi sysupgrade

Signed-off-by: Ram Chandra Jangir <rjangir@codeaurora.org>
(backported from dc6af375441eeb2ba9143c2d85d6c91534703d10)