[Mesa-stable] [MR] Revert "egl: Add a 565 pbuffer-only EGL config under X11."

[Andres Gomez]

This reverts commit dacb11a5.

The reason for introducing this change was to fulfill CTS's requirement
to be able to run a 565-no-depth-no-stencil config for ES 3.0 on X11.

Unfortunately, enabling this causes other problems. The most relevant
one is that, for i965, CTS was passing for GL 4.5 and now it fails
while trying to run the "41" configs that have been activated by this
change.

While we don't have a proper solution for this "regression", it is
better to go back to the previous state.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110357


https://gitlab.freedesktop.org/mesa/mesa/merge_requests/963

-- 
Br,

Andres