drm/panel/panel-ilitek-9341: Use fbdev-dma

Implement fbdev emulation with fbdev-dma. Fbdev-dma now supports
damage handling, which is required by panel-ilitek-9341. Avoids
the overhead of fbdev-generic's additional shadow buffering. No
functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Jessica Zhang <quic_jesszhan@quicinc.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-28-tzimmermann@suse.de