ASoC: Tegra: utils: Don't use global variables

Instead, have the machine driver provide storage for the utility data
somehow.

For Harmony in particular, store this within struct tegra_harmony, itself
referenced by snd_soc_card's drvdata.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>