ARM: zynq: Add Z-turn board V5

ARM: zynq: Add Z-turn board V5

Adding Z-turn board V5 to resolve the change between:

"Z-TURNBOARD_schematic.pdf" schematics state version 1 to 4 has Atheros AR8035
"Z-Turn_Board_sch_V15_20160303.pdf" schematics state version 5 has Micrel KSZ9031

Changes v1 -> v2: Instead of using new board, the v2 using a common devicetree
for z-turn boards (zynq-zturn-common.dtsi) and for each board a specific DT

Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info>
Link: https://lore.kernel.org/r/20201126070516.85882-1-agriveaux@deutnet.info
Signed-off-by: Michal Simek <michal.simek@xilinx.com>