ARM: at91/dt: sama5d3 xplained: add phy address for macb1

After 57a38eff

 (net: phy: micrel: disable broadcast for KSZ8081/KSZ8091)
the macb1 interface refuses to work properly because it tries
to cling to address 0 which isn't able to communicate in broadcast with
the mac anymore. The micrel phy on the board is actually configured
to show up at address 1.
Adding the phy node and its real address fixes the issue.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: <stable@vger.kernel.org> #3.19
Signed-off-by: Olof Johansson <olof@lixom.net>