realtek: fix dts warnings.

realtek: fix dts warnings.

Currently following warnings are given

dts/rtl930x.dtsi:166.4-23: Warning (reg_format):
/switchcore@1b000000/i2c@36c:reg: property has invalid length
(8 bytes) (#address-cells == 2, #size-cells == 1)

Obviously default address-cells size is fixed to 64 bit. Align
with upstream and override address size to 32 bit.

Suggested-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/20091
Signed-off-by: Robert Marko <robimarko@gmail.com>