While GNOME does require hardware acceleration, GNOME's X11 mode
(not sure about Wayland mode) does work without DRM support, so
it works fine with software rendering on devices without a working
GPU as long as fbdev works.
I think this raises the question of whether we should rename
pmb:hw-accel to pmb:drm as e.g. Phosh should work without 3D
acceleration if a device e.g. uses a kernel with SimpleDRM support,
but that is out of scope for this MR/commit.
Effectively reverts 638362de63edbf9b166d6909b5be3a7094a08f46
[ci:skip-vercheck]
50f392df43