ASoC: tegra: select REGMAP_MMIO

All Tegra ASoC drivers will be reworked to use MMIO regmaps. Select
this in Kconfig.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/tegra/Kconfig

 config SND_SOC_TEGRA
 	tristate "SoC Audio for the Tegra System-on-Chip"
 	depends on ARCH_TEGRA && TEGRA_SYSTEM_DMA
+	select REGMAP_MMIO
 	help
 	  Say Y or M here if you want support for SoC audio on Tegra.