Implement fbdev emulation with fbdev-shmem. Avoids the overhead of
fbdev-generic's additional shadow buffering. No functional changes.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Deepak Rawat <drawat.floss@gmail.com>
Reviewed-by: Deepak Rawat <drawat.floss@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-12-tzimmermann@suse.de