drm/<drivers>: Drop fbdev info flags

drm/<drivers>: Drop fbdev info flags

- FBINFO_CAN_FORCE_OUTPUT has been a lie ever since we nerfed&removed
  the entire panic handling code in our fbdev emulation. We might
  restore kms panic output, but not through the bazillion of legacy
  code layers called fbdev/fbcon, there's just no way to make that
  work safely.

- With the module check change FBINFO_DEFAULT is always 0, so can be
  removed too.

That removes another change to cargo-cult stuff in kms drivers, yay!

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170706125735.28299-5-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>