[PATCH] atyfb: Improve blanking

Force blanking signal and disable display requests when blanked.  Don't
disable LCD backlight with FB_BLANK_NORMAL.

Signed-off-by: Ville Syrjälä <syrjala@sci.fi>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>