vaapi: prefix USE_FOO defines to fix build with mesa 22.3.0
Apparently mesa 22.3.0 has updated the egl headers, and eglplatform.h now
contains commit
https://github.com/KhronosGroup/EGL-Registry/pull/130/commits/
3670d645f4a26a0a9e87e7f3a8608e7cc1d53b5b
after which xlib headers don't get included by default anymore but are
dependent upon whether USE_X11 was defined.
This breaks headless builds of gstreamer-vaapi because we always define
an internal define USE_X11 as either 1 or 0.
Change these defines to GST_VAAPI_USE_XYZ instead to avoid this.
Fixes #1634
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3555>