ARM: dts: am3517-craneboard: remove unneeded unit name for fixedregulator

This patch fixes the following DTC warnings for am3517-craneboard.dtb:

"fixedregulator@0 has a unit name, but no reg property"

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>