drm/rockchip: remove unneeded semicolon from vop2 driver

Eliminate the following coccicheck warning:
./drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:1476:2-3: Unneeded
semicolon

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220505232659.4405-1-yang.lee@linux.alibaba.com