drm: zynqmp_dp: Downgrade log level for aux retries message

Enable this message for verbose debugging only as it is otherwise
printed after every AUX message, quickly filling the log buffer.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240423171859.3953024-4-sean.anderson@linux.dev