video: fbdev: udlfb: drop log level for blanking

Drop log level for blanking from info to debug. Xorg likes to habitually
unblank when already unblanked and this can fill up logs over a long period
of time.

Signed-off-by: Mike Gerow <gerow@google.com>
Cc: bernie@plugable.com
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>