ARM: dts: BCM5301X: Add support for Linksys EA9500

ARM: dts: BCM5301X: Add support for Linksys EA9500

Hardware Info
-------------

Processor	- Broadcom BCM4709C0KFEBG dual-core @ 1.4 GHz
Switch		- BCM53012 in BCM4709C0KFEBG & external BCM53125
DDR3 RAM	- 256 MB
Flash		- 128 MB (Toshiba TC58BVG0S3HTA00)
2.4GHz		- BCM4366 4×4 2.4/5G single chip 802.11ac SoC
Power Amp	- Skyworks SE2623L 2.4 GHz power amp (x4)
5GHz x 2	- BCM4366 4×4 2.4/5G single chip 802.11ac SoC
Power Amp	- PLX Technology PEX8603 3-lane, 3-port PCIe switch
Ports		- 8 Ports, 1 WAN Ports
Antennas	- 8 Antennas
Serial Port	- @J6 [GND,TX,RX] (VCC NC)    115200 8n1

Tested with OpenWrt built with DSA driver and Kernel v4.14

Signed-off-by: Vivek Unune <npcomplete13@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>