arm64: dts: colibri-imx8x: Correct pull on lcdif

The pads USDHC1_RESET_B and MCLK_IN1 need a pull-down instead of
pull-disabled. Correct this.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>