ALSA: hda: Support disabling of clocks for Tegra

ALSA: hda: Support disabling of clocks for Tegra

This change is basically a WAR. Tegra T30 HDA controller does not
support presence detect event generateion when all HDA clocks are
off. This change forcefully enables power disabling of HDA chip and
clocks while not in use. As a side effect Tegra HDA driver misses
the unsolicited HDMI plug in event when in power off mode. To overcome
this limitation whenever user space tries to open an HDMI pcm stream
Tegra HDA controller requests HDMI driver to setup presence detect
registers after enabling the chip and waits until it gets valid ELD
data.

Bug 904530

Change-Id: I8c8cb6fe7935ba8b16c421beca68cb1d7f576212
Signed-off-by: Sumit Bhattacharya <sumitb@nvidia.com>
Reviewed-on: http://git-master/r/66972
Reviewed-by: Scott Peterson <speterson@nvidia.com>
Rebase-Id: R3ee2f4a750922ed8bba16505401f995fa7ea508c