ARM: dts: at91-sama5d27_som1: fix phy address to 7

Fix the phy address to 7 for Ethernet PHY on SAMA5D27 SOM1. No
connection established if phy address 0 is used.

The board uses the 24 pins version of the KSZ8081RNA part, KSZ8081RNA
pin 16 REFCLK as PHYAD bit [2] has weak internal pull-down.  But at
reset, connected to PD09 of the MPU it's connected with an internal
pull-up forming PHYAD[2:0] = 7.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Fixes: 2f61929e ("ARM: dts: at91: at91-sama5d27_som1: fix PHY ID")
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: <stable@vger.kernel.org> # 4.14+