drm/panel-simple: drop use of data-mapping property

The "data-mapping" property may not be the best way to describe the
interface between panels and display interfaces.
Drop use of in the panel-simple driver, so we have time to find
the right way to describe this interface.

Fixes: 4a1d0dbc ("drm/panel: simple: add panel-dpi support")
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200314153047.2486-3-sam@ravnborg.org

drivers/gpu/drm/panel/panel-simple.c

@@ -361,7 +361,6 @@ static int panel_dpi_probe(struct device *dev,
 	struct panel_desc *desc;
 	unsigned int bus_flags;
 	struct videomode vm;
-	const char *mapping;
 	int ret;
 
 	np = dev->of_node;
@@ -386,16 +385,6 @@ static int panel_dpi_probe(struct device *dev,
 	of_property_read_u32(np, "width-mm", &desc->size.width);
 	of_property_read_u32(np, "height-mm", &desc->size.height);
 
-	of_property_read_string(np, "data-mapping", &mapping);
-	if (!strcmp(mapping, "rgb24"))
-		desc->bus_format = MEDIA_BUS_FMT_RGB888_1X24;
-	else if (!strcmp(mapping, "rgb565"))
-		desc->bus_format = MEDIA_BUS_FMT_RGB565_1X16;
-	else if (!strcmp(mapping, "bgr666"))
-		desc->bus_format = MEDIA_BUS_FMT_RGB666_1X18;
-	else if (!strcmp(mapping, "lvds666"))
-		desc->bus_format = MEDIA_BUS_FMT_RGB666_1X24_CPADHI;
-
 	/* Extract bus_flags from display_timing */
 	bus_flags = 0;
 	vm.flags = timing->flags;