arm64: dts: debix-a: Disable i2c2 in base .dts

arm64: dts: debix-a: Disable i2c2 in base .dts

The I2C2 bus is used for the CSI and DSI connectors only, no devices are
connected to it on neither the Debix Model A nor its IO board. Disable
the bus in the board's .dts and remove its clock frequency settings, as
the value depends solely on the devices conncted to the CSI and DSI
connectors. Display panel or camera sensor overlays will configure and
enable the bus when necessary.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>