drm/ssd130x: Replace simple display helpers with the atomic helpers

drm/ssd130x: Replace simple display helpers with the atomic helpers

The simple display pipeline is a set of helpers that can be used by DRM
drivers to avoid dealing with all the needed components and just define
a few functions to operate a simple display device with one full-screen
scanout buffer feeding a single output.

But it is arguable that this provides the correct level of abstraction
for simple drivers, and recently some have been ported from using these
simple display helpers to use the regular atomic helpers instead.

The rationale for this is that the simple display pipeline helpers don't
hide that much of the DRM complexity, while adding an indirection layer
that conflates the concepts of CRTCs and planes. This makes the helpers
less flexible and harder to be reused among different graphics drivers.

Also, for simple drivers, using the full atomic helpers doesn't require
a lot of additional code. So adding a simple display pipeline layer may
not be worth it.

For these reasons, let's follow that trend and make ssd130x a plain DRM
driver that creates its own primary plane, CRTC, enconder and connector.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905222759.2597186-1-javierm@redhat.com