[PATCH] atyfb: Reduce verbosity

Don't complain about invalid modes when FB_ACTIVATE_TEST is used.

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>