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

This reverts commit 95bf25bb.

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/60dc7697-d7a0-4bf4-a22e-32f1bbb792c2@suse.de



Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306063721.1.I4a32475190334e1fa4eef4700ecd2787a43c94b5@changeid