T104xD4RDB: Fix PHY address for PHY connected to FM1@DTSEC3

On T1040D4RDB board, u-boot fails to connect port FM1@DTSEC3 to
the Ethernet PHY because the wrong PHY address is used. Also,
T1040D4RDB supports SGMII on one port only.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>