ariable omap_runtime_data.period_index.

Tested on OMAP5910 based Amstrad Delta (E3) using work in progress ASoC
driver.

Based on linux-2.6-asoc.git v2.6.31-rc1.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Äf: