Revert "drm/udl: Add ARGB8888 as a format"

This reverts commit 95bf25bb9ed5dedb7fb39f76489f7d6843ab0475.

Apparently there was a previous discussion about emulation of formats
and it was decided XRGB8888 was the only format to support for legacy
userspace [1]. Remove ARGB8888. Userspace needs to be fixed to accept
XRGB8888.

[1] https://lore.kernel.org/r/[e-mail]

Acked-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Javier Martinez Canillas <[e-mail]>
Signed-off-by: Douglas Anderson <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306063721.1.I4a32475190334e1fa4eef4700ecd2787a43c94b5@changeid

drivers/gpu/drm/udl/udl_modeset.c

···
 static const uint32_t udl_primary_plane_formats[] = {
 	DRM_FORMAT_RGB565,
 	DRM_FORMAT_XRGB8888,
-	DRM_FORMAT_ARGB8888,
 };
 
 static const uint64_t udl_primary_plane_fmtmods[] = {