ARM: dts: omap5-igep0050.dts: Use tabs for indentation

And here's another nitpick ;-)

Cc: Agustí Fontquerni i Gorchs <afontquerni@iseebcn.com>
Cc: Enric Balletbo Serra <eballetbo@gmail.com>
Cc: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Pau Pajuel <ppajuel@gmail.com>
Fixes: b118c6a6

 ("ARM: dts: Add power button support for igepv5")
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>