ASoC: omap3pandora: Fix compilation error

Fixes:
sound/soc/omap/omap3pandora.c: In function ‘omap3pandora_dac_event’:
sound/soc/omap/omap3pandora.c:92:19: error: request for member ‘dev’ in something not a structure or union
make[3]: *** [sound/soc/omap/omap3pandora.o] Error 1

Which is introduced by:
dd194b4 ASoC: omap: Check regulator enable for DAC on Pandora

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>