ARM: OMAP2+: omap2plus_defconfig: Enable Atheros support

Enable Atheros 803X phy driver support in defconfig which is present in
AM335x EVM and EVM Starter Kit.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>