ARM: zynq: DT: Move size/address properties to dtsi

Move the GEM's size and address cells properties to the common
dtsi file.

Cc: Andreas Färber <afaerber@suse.de>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>