drm/fbdev: fix cloning on fbcon

Simple cloning rules compared to server:
(a) single crtc
(b) > 1 connector active
(c) check command line mode
(d) try and find 1024x768 DMT mode if no command line.
(e) fail to clone

Signed-off-by: Dave Airlie <airlied@redhat.com>
3 files changed