ARM: dts: omap3-beagle-xm: remove unneeded unit names

This patch fixes the following DTC warnings for omap3-beagle-xm.dtb:

"encoder@0 has a unit name, but no reg property"
"encoder@0/ports/port@0/endpoint@0 has a unit name, but no reg property"
"encoder@0/ports/port@1/endpoint@0 has a unit name, but no reg property"
"connector@0 has a unit name, but no reg property"
"connector@1 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>