drm/arc: Initialize sim connector before display pipe

That way we can get rid of this final piece of init code, and use the
simple pipe helpers as intended.

v2: Fix indent (Sam)

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112084358.2771527-14-daniel.vetter@ffwll.ch