ARM: dts: ethernut5: Fix the build warning

ARM: dts: ethernut5: Fix the build warning

Fix the building warning as below:
---8<----
Warning (reg_format): "reg" property in /i2c-gpio-0/pcf8563@50 has invalid length (4 bytes) (#address-cells == 2, #size-cells == 1)
Warning (avoid_default_addr_size): Relying on default #address-cells value for /i2c-gpio-0/pcf8563@50
Warning (avoid_default_addr_size): Relying on default #size-cells value for /i2c-gpio-0/pcf8563@50
--->8----

Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>
Reviewed-by: Tom Rini <trini@konsulko.com>