clk: rockchip: rk3368: fix parents of video encoder/decoder

The vdpu and vepu clocks can also be parented to the npll and current
parent list also is wrong as it would use the npll as "usbphy" source,
so adapt the parent to the correct one.

Fixes: 3536c97a ("clk: rockchip: add rk3368 clock controller")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: zhangqing <zhangqing@rock-chips.com>
Cc: stable@vger.kernel.org