ARM: davinci_all_defconfig: enable DA850 audio as modules

Build audio support for DA850-based devices as modules in the default
defconfig.

Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>