ARM: at91/dt: define phy available on sama5d3 mother board

This patch describe the phy used on atmel sama5d3 mother board:
 - phy address
 - phy interrupt pin

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: David S. Miller <davem@davemloft.net>