clk: imx8mq: Add VIDEO2_PLL clock

This clock is needed by DCSS when high resolutions are used.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@nxp.com>
CC: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>