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.