ASoC: tegra20_ac97: Remove __devinitconst attribute

__devinitconst has been removed from the kernel and gives
the following build errors:
sound/soc/tegra/tegra20_ac97.c:460:58: error: Expected ; at end of declaration
sound/soc/tegra/tegra20_ac97.c:460:58: error: got __devinitconst

Cc: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>