gstreamer1.0-vaapi: upgrade to version 1.12.2

gstreamer1.0-vaapi: upgrade to version 1.12.2

* Remove backported patch:
  1. vaapivideobufferpool-create-allocator-if-needed.patch

* Add PACKAGECONFIG_GL variable to make it possible for BSP layers to
  customize what should be the default, EGL or GLX

* Set virtual/egl instead of virtual/mesa as egl dependency in case
  platform specific drivers provide virtual/egl functionality

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>