[gstreamer] incorrect path for gstreamer headers

[vojtadavid]

Gstreamer headers are installed with prefix /some/include/path/gstreamer-1.0/gst/gst.h but all gstreamer headers expect include path without the gstreamer-1.0 i.e. /some/include/path/gst/gst.h

This was already discusse here #26417 but it was never fixed