ASoC TFA9890: check pcm start flag to trigger cfg file switch

if pcm is already started and dsp pll is not yet in sync, schedule
worker thread to switch cfg file.

Change-Id: I20982bf9c2c527d7258398394176b574c6dc0d29
Signed-off-by: Prabhu Annabathula <prabhu.annabathula@motorola.com>