dts: arm: xilinx: Remove improper range property

Remove 'ranges' property from gpio node as it shouldn't be there
since we aren't converting 1:1 between address spaces.  This fixes
the following DTC warning:

   Warning (ranges_format): /soc/gpio@e000a000:ranges: empty "ranges"
   property but its #size-cells (0) differs from /soc (1)

Signed-off-by: Kumar Gala <galak@kernel.org>