usb: musb: mpfs: detect UPLI external vbus control requirement from DT

The musb driver core already supports external vbus control for ULPI
PHYs, but none of the drivers actually enable it. A customer reported
needing this for their device, and now that a DT property for detecting
this configuration exists, read the property to enable the feature.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240531-spilt-garage-ed2113d628e8@wendy


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>