[ARM] 4645/1: Cyberpro: Trivial fix to restore 16bpp mode.

Cyberpro: when user requests 16bpp, use it and not 24bpp.
There was a missing break causing requests for 16bpp mode
to end up in 24bpp mode.

Signed-off-by: Jan Rinze Peterzon <janrinze@home.nl>
Acked-by: Ralph Siemsen <ralphs@netwinder.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>