video: sunxi_display: Convert to DM_VIDEO

DM_VIDEO migration deadline is already expired, but around
80 Allwinner boards are still using video in a legacy way:

===================== WARNING ======================
This board does not use CONFIG_DM_VIDEO Please update
the board to use CONFIG_DM_VIDEO before the v2019.07 release.
Failure to update by the deadline may result in board removal.
See doc/driver-model/migration.rst for more info.
====================================================

Convert the legacy video driver over to the DM_VIDEO framework. This is
a minimal conversion: it doesn't use the DT for finding its resources,
nor does it use DM clocks or DM devices for the outputs (LCD, HDMI, CVBS).

Tested in Bananapi M1+ Plus 1920x1200 HDMI out. (Jagan)

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
[Andre: rebase and smaller fixes]
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index 0135575..a29d115 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -816,13 +816,14 @@
 	depends on !MACH_SUN9I
 	depends on !MACH_SUN50I
 	depends on !SUN50I_GEN_H6
-	select VIDEO
+	select DM_VIDEO
+	select DISPLAY
 	imply VIDEO_DT_SIMPLEFB
 	default y
 	---help---
-	Say Y here to add support for using a cfb console on the HDMI, LCD
-	or VGA output found on most sunxi devices. See doc/README.video for
-	info on how to select the video output and mode.
+	Say Y here to add support for using a graphical console on the HDMI,
+	LCD or VGA output found on older sunxi devices. This will also provide
+	a simple_framebuffer device for Linux.
 
 config VIDEO_HDMI
 	bool "HDMI output support"