DashPlayer: Notify position for video EOS buffer immediately

Notify current rendering position for video EOS buffer immediately,
without waiting for 100ms between subsequent updates.

CRs-Fixed: 489546
Change-Id: I16e218f85db2c1c33d5e8b4b7452f60f7a863c67
Signed-off-by: Hieu Phan <aznrice2k4@gmail.com>