ARM: dts: armada-xp-rn2120: drop wrong compatible for i2c0

The compatible is supposed to be "marvell,mv78230-i2c", "marvell,mv64xxx-i2c",
as provided by armada-xp.dtsi.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>