Avoid the following checkpatch warnings:

arch/arm/boot/dts/imx6qdl-phytec-mira-peb-av-02.dtsi:67: error: code
 indent should use tabs where possible
arch/arm/boot/dts/imx6qdl-phytec-mira-peb-av-02.dtsi:67: warning:
 please, no spaces at the start of a line
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>