Fixed segfault for Broadwell platforms and above.
Fixed segfault for Broadwell platforms and above.

Dynamic loading of special iHD surface handling functions only works for Haswell in MSS 2016 Linux. For MSS 2017 and above, such functions are now handled by standard libva functions vaAcquireBufferHandle() and vaReleaseBufferHandle(). This commit fixes a segfault unintentionally caused a cleanup commit 55e9d96.

ishmael1985/gstreamer-media-SDK,ph0b/gstreamer-media-SDK