video: squash lines for immediate return

For vidconsole_post_probe(), it is common coding style to let a
probe method return the value of a register function.

The others will become simple wrapper functions.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@nvidia.com>