Fixes earlier problems where monitor would not return from blank

Test with any DisplayLink-based USB 2.0 graphics adapter
sudo nano /sys/class/graphics/fb?/blank
and write out single digit FB_BLANK_* code from include/linux/fb.h

Supports on (0), blank (1), suspend (2,3), powerdown (4)
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>