rockchip: video: Kconfig: reformat help for VIDEO_ROCKCHIP

For consistency sake (and as we are about to add new options to this
file), reformat the help for VIDEO_ROCKCHIP.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>