ARM: zynq: Add partition description

Xilinx is using standard mtd partition layout for quite a long time. It is
used for testing purpose on evaluation boards.
Also #address/size-cells shouldn't be present without nodes which should
use them that's why move them from zynq-7000.dtsi to nand/nor nodes
directly.

The patch was tested on zc706 and zedboard(with also increasing max
frequency and rx bus width).

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/4c3348981bba32d3892194420d78fe8621c47534.1698837725.git.michal.simek@amd.com