Stream: Fix mmap usecase handling for speaker

Speaker device start starts VI feedback graph and configures speaker
protection module in RX graph. During ULL usecase, if device switch
to speaker happens in STREAM_STOPPED state, graph_change/graph_prepare
is called for Speaker graph without dev->start(). This causes Speaker
payload not getting sent to ADSP before graph_prepare leading to improper
behaviour in ADSP. Move dev->start() for speaker ULL usecases before
graph_open to avoid such scenarios.

Change-Id: Ie3a63942febeafa0979826c606b7755eb4e6c9e7
2 files changed