ARM: multi_v7_defconfig: Fix STi support

This patch adds ST serial driver (st-asc) and ICPLUS ethernet PHY to
multi_v7_defconfig. All STi based SOCs use ST-ASC as default serial
console, and most of the STi SOC based boards have ICPLUS external
ethernet PHY. These two options makes the system boot nfs root with
console.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Olof Johansson <olof@lixom.net>