arm64: dts: marvell: armada-37xx: declare USB2 UTMI PHYs

On Marvell Armada 3700 SoCs there are two USB2 UTMI PHYs. They are
both very similar but only one has OTG/charging capabilities.

Because there are USB host registers and PHY registers mixed in a
single area, a system controller is also created and referenced from
both the USB host node and the PHY node.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>