drm/panel: panel-simple: Fix proper bpc for AM-1280800N3TZQW-T00H

AM-1280800N3TZQW-T00H panel support 8 bpc not 6 bpc as per
recent testing in i.MX8MM platform.

Fix it.

Fixes: bca684e6 ("drm/panel: simple: Add AM-1280800N3TZQW-T00H")
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211111094103.494831-1-jagan@amarulasolutions.com

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

@@ -720,7 +720,7 @@ static const struct drm_display_mode ampire_am_1280800n3tzqw_t00h_mode = {
 static const struct panel_desc ampire_am_1280800n3tzqw_t00h = {
 	.modes = &ampire_am_1280800n3tzqw_t00h_mode,
 	.num_modes = 1,
-	.bpc = 6,
+	.bpc = 8,
 	.size = {
 		.width = 217,
 		.height = 136,