ARM: multi_v7_defconfig: Enable A10 audio codec driver as module

The A10 audio codec driver supports the on-chip audio codec found on
Allwinner A10, A10s, A13, A20 SoCs.

Build it as a module, since it is not critical.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>