uvesafb: change mode parameter to mode_option

Make more drivers use the "mode_option" parameter.  This one is quite new
so drop the old "mode" parameter before someone starts using it seriously.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>