arm64: dts: imx8mp-kontron: Fix USB OTG role switching

arm64: dts: imx8mp-kontron: Fix USB OTG role switching

The VBUS supply regulator is currently assigned to the PHY node.
This causes the VBUS to be always on, even when the controller
needs to be switched to peripheral mode.

Fix the OTG role switching by adding a connector node and moving
the VBUS supply regulator to that node. This way the VBUS gets
correctly switched according to the current role.

Fixes: 946ab10e3f40 ("arm64: dts: Add support for Kontron OSM-S i.MX8MP SoM and BL carrier board")
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>