gstreamer1.0-python: package the internal libraries explicitly

setuptools3-base FILES assignments have been simplified, therefore the
internal libraries should be now packaged explicitly.

Fixes
ERROR: QA Issue: gstreamer1.0-python: Files/directories were installed but not shipped in any package:
  /usr/lib/gstreamer-1.0/libgstpython.so

Signed-off-by: Khem Raj <raj.khem@gmail.com>

Author: kraj

recipes-multimedia/gstreamer/gstreamer1.0-python_1.20.3.imx.bb

@@ -28,3 +28,5 @@ def get_gst_ver(v):
     return oe.utils.trim_version(v, 3)
 
 inherit meson pkgconfig setuptools3-base upstream-version-is-even
+
+FILES:${PN} += "${libdir}/gstreamer-1.0"