NuPlayerRender: Fix uint32_t numFramesPendingPlayout overrun issue

Add protection to avoid uint32_t numFramesPendingPlayout overrun.
If overrun happens, the video will be post a large delay time casuing video frozen.

Change-Id: Ia5d3aa06a61d40ea08cec525ec315ce0858c8854
Author: Feng Xiao<fengx.xiao@intel.com>
Signed-off-by: Feng Xiao<fengx.xiao@intel.com>
Signed-off-by: Yi Wang<yi.a.wang@intel.com>
Singed-off-by: Shuo Gao <shuo.gao@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 48710, 27202