hal: fix glitch heard when FM playback started

When FM started by "handle_fm", then a routing request followed,
for platforms with wsa speaker enabled, this will lead FM stopped
immediately just started and then started again. So some glitches
can be heard.

Revert this as wsa speaker can be enabled successfully now without
stop fm first then start it again

Change-Id: I1ec64d469314670c0906f89ef763e9b8f7a56982
CRs-Fixed: 891536