drm/meson: Fix error handling when afbcd.ops->init fails

When afbcd.ops->init fails we need to free the struct drm_device. Also
all errors which come after afbcd.ops->init was successful need to exit
the AFBCD, just like meson_drv_unbind() does.

Fixes: d1b5e41e ("drm/meson: Add AFBCD module driver")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211230235515.1627522-3-martin.blumenstingl@googlemail.com