KMS drivers really should all be able to restore their display state
on resume without fbcon helping out. So make this the default.

Since I'm not entirely foolish, make it only a default, which drivers
can still override. That way when the inevitable regression report
happens I can fix things up with a one-liner plus FIXME comment that
someone should fix up the suspend/resume code in that driver.

But at least all new drivers won't be broken by accident as soon as
you turn off fbcon because "suspend/resume worked when I tested it".

v2: Keep this for radeon because of

commit 18c437ca
Author: Alex Deucher <alexander.deucher@amd.com>
Date:   Tue Nov 14 17:19:29 2017 -0500

    Revert "drm/radeon: dont switch vt on suspend"

Thanks to Michel Dänzer for pointing this one out.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Michel Dänzer <michel@daenzer.net>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Samuel Li <Samuel.Li@amd.com>
Cc: "Michel Dänzer" <michel.daenzer@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Junwei Zhang <Jerry.Zhang@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Shirish S <shirish.s@amd.com>
Cc: Daniel Stone <daniels@collabora.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: intel-gfx@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Samuel Li <samuel.li@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181127173424.301-1-daniel.vetter@ffwll.ch