video: Add an option to skip video initialization

video: Add an option to skip video initialization

This patch adds an option to skip the video initialization on for all
video drivers. This is needed for the CPCI750 which can be built as
CPCI host and adapter/target board. And the adapter board can't
access the video cards located on the CompactPCI bus.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Anatolij Gustschin <agust@denx.de>
Rebased against simplifying patch.
Signed-off-by: Wolfgang Denk <wd@denx.de>