ASoC: lahaina: update enable/disable audio core vote for mi2s

Check and enable audio core vote only when reference count of
mi2s is 1 and disable only when reference count is 0.

Change-Id: If6a8c18feec30fa83363804d5160fd6996aa0319
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>
Signed-off-by: Vignesh Kulothungan <vigneshk@codeaurora.org>