ARM: imx6q: clk: Parent DI clocks to video PLL via di_pre_sel

Route the video PLL to the display interface clocks via the di_pre_sel
and di_sel muxes by default.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>