Add restriction about setting MEDIA_STREAMER_PARAM_DISPLAY

Add restriction about setting MEDIA_STREAMER_PARAM_DISPLAY

- MEDIA_STREAMER_PARAM_DISPLAY should be set in main thread.
  Otherwise, it will return MEDIA_STREAMER_ERROR_INVALID_OPERATION by internal restriction.
  To avoid MEDIA_STREAMER_ERROR_INVALID_OPERATION in sub thread, ecore_thread_main_loop_begin() and
  ecore_thread_main_loop_end() can be used, but deadlock can be also occurred if main thread is busy.

[Version] 0.1.79
[Issue Type] Improvement

Change-Id: Ie7290e99d6e051b363760421b18b4702b39acee0
Signed-off-by: Hyunil <hyunil46.park@samsung.com>