mm-video: vdec: fix read of command line args in test app

The display window information should only be read if
display option is selected and thumbanil mode is not
selected. Without this change, display window variable
was getting unnecessarily initialized and caused the
last parameter - num_frames_to_decode to default to 255.
This lead the omx test app to send EOS after 255 frames.

Change-Id: I6eb9243dffd4f72eeba2f20bf3c749bee8bc328d
1 file changed