pal: use default value if preroll is not set with 2nd stage enabled

Sometimes apk may not set preroll duration, causing 2nd stage
detection performance down.

Add default preroll values in rm xml and use it when preroll
is not set by client and 2nd stage is enabled.

Change-Id: Id50cdee5a9d7959d5f812eae4f0144d71eb15f89
15 files changed