ARM: dts: BCM5301X: Add basic DT for Linksys EA6300 V1

It's wireless home router based on BCM4708A0 with BCM4360 + BCM43217
wireless chipsets. LEDs will be hopefully added later to the DT.
According to some sources it may use the same board as EA6400 and just
differ by an original vendor firmware.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>