arm64: dts: exynos: Add OF graph between USB-PHY and MUIC

OF graph describes USB data lanes between USB-PHY and respective MUIC.
Since graph is present and DWC driver can use it to get extcon, obsolete
extcon property can be removed.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>