asoc: tegra: need to enable ahub clocks before accessing DAM registers

To avoid hard hang when you execute the below command lines

- cat /sys/kernel/debug/asoc/tegra30-dam.0
- cat /sys/kernel/debug/asoc/tegra30-dam.1
- cat /sys/kernel/debug/asoc/tegra30-dam.2

Bug 1283024

Change-Id: I1c18bd5c1bbf6059930b8bbb279e4a8596c85bdd
Signed-off-by: Haley Teng <hteng@nvidia.com>