fbcon: use mode from fbconsole to enable dc

fbcon: use mode from fbconsole to enable dc

fbconsole takes over when a userspace entity (Xorg) gets
killed. But in this scenario, DC was getting enabled
with X's mode instead of using fbconsole's mode. This
lead to DC and fbconsole having different modes if X had
updated its mode earlier. Updated fbconsole unblanking logic
to use fbconsole's mode to enable DC during a switch from
graphical to text mode.

bug 1885932

Change-Id: I8aa63c950fefc23aa2ec1b062ed6648688b6f4bb
Signed-off-by: Naveen Kumar S <nkumars@nvidia.com>
Reviewed-on: http://git-master/r/1498522
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>