GF-61229: At the end of video stream, the knob indicate unexpected position on dummy area.

WHEN current time is bigger than duration, the knob deviate from slider.
So, I have added clamping inValue for knob position.

DCO-1.1-Signed-Off-By: Jungchae Kim <jungchae.kim@lge.com>
Merge pull request #1124 from enyojs/GF-61229-Jungchae

GF-61229: At the end of video stream, the knob indicate unexpected position