clk: imx6: fix video_27m parent for IMX6QDL_CLK_CKO1_SEL

q/dl datasheets list the 5th selection value for ck01_sel as
video_27M_clk_root.

By replacing the dummy value we then can set IMX6QDL_CLK_VIDEO_27M
as parent for IMX6QDL_CLK_CKO1_SEL.

Signed-off-by: Philipp Puschmann <pp@emlix.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>