media: dvb: Enhance parsing of SDMX results

While playing from memory, it may happen that demux thread
is stalled while parsing SDMX results due to PULL mode.
While thread is stalled it is possible that the user asks
to stop and start some of the secure filters.

When thread gets back from stalling, it may parse the results
of a filter that was restarted while the thread was stalled,
even-though this information is not relevant anymore since
filter was restarted.

Change-Id: I341e025a973df2935741eee2533f250f4190a605
Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>