ASoC: wm9713: Move driver state struct allocation to driver probe

Resources for the device should be allocated in the device driver probe
callback, rather than in the ASoC CODEC probe callback.

E.g. one advantage is that we can use device managed allocations.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>