The cirrus driver maintains plane state, format and pitch, in it's
device structure. Introduce a plane state for the primary plane to
store the values.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230215161517.5113-16-tzimmermann@suse.de