drm/simpledrm: Use fbdev defaults for shadow buffering

commit 029c5eb0a8a965e08d0960539f4c3834d05ed08f from
https://nv-tegra.nvidia.com/r/3rdparty/canonical/linux-jammy.git jetson_36.3

Don't select shadow buffering for the fbdev console explicitly. The
fbdev emulation's heuristic will enable it for any framebuffer with
.dirty callback.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303205839.28484-2-tzimmermann@suse.de
(cherry picked from commit d7442505

)
Change-Id: Icf5f77a9b12676628cfb37c0b8e34853de996394
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/3rdparty/canonical/linux-jammy/+/2985836
Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>
Signed-off-by: Rajeshkumar Ramasamy <rajeshkumar.ramasamy@windriver.com>