drm/rockchip: Don't spam logs in atomic check

Userspace should not be able to trigger DRM_ERROR messages to spam the
logs; especially not through atomic commit parameters which are
completely legitimate for userspace to attempt.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Fixes: 7707f722

 ("drm/rockchip: Add support for afbc")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230808104405.522493-1-daniels@collabora.com