Enabling idle mode during audio playback causes the glitches on OMAP5
HDMI. The TRM also suggests to use no-idle for HDMI audio playback.

This patch sets HDMI idle mode to no-idle for the duration of the
playback, and restores it back to original value afterwards.
Signed-off-by: NJyri Sarha <jsarha@ti.com>
Reviewed-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>