drm/rockchip: Fix Copyright description

The company name has update to Rockchip Electronics Co., Ltd.
since 2021.
And change Co.Ltd to Co., Ltd. to fix mail server warning:
DBL_SPAM(6.50)[co.ltd:url];

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20241214071333.3325308-1-andyshrk@163.com