ARM: dts: msm: Add dpdm regulator handler on sdxprairie

PM8150B charger requires a reference to USB PHY which exposes
a DPDM regulator to be enabled prior to performing charger type
detection. Using same reference usb driver checks for dpdm
regulator status before starting dwc3 state machine as it might
interfere with apsd (automatic power source detection).

Change-Id: If3c11acb3673c43a6dcc0c50191cf10057d28889
Signed-off-by: Mayank Rana <mrana@codeaurora.org>