drm/sysfb: corebootdrm: Support panel orientation

drm/sysfb: corebootdrm: Support panel orientation

Add fields and constants for coreboot framebuffer orientation. Set
corebootdrm's DRM connector state from the values. Not all firmware
provides orientation, so make it optional. Systems without, continue
to use unknown orientation.

v3:
- comment on _HAS_ORIENTATION semantics (Tzung-Bi)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Julius Werner <jwerner@chromium.org>
Acked-by: Tzung-Bi Shih <tzungbi@kernel.org> # coreboot
Link: https://patch.msgid.link/20260217155836.96267-13-tzimmermann@suse.de