ARM: dts: msm: Enable USB SS mode for Khaje

QMP PHY's vdd-supply is connected to an external
regulator which is controlled by PMIC GPIO 1 on Khaje.
This change adds support for eLDO9(external regulator)
to enable USB SS mode.

Change-Id: I109ba2272a67e1bef1e9456a0f6052e738a36464