usb: phy: Clean up phy-msm-ssusb to enable LDOs on init

Clean up phy-msm-ssusb driver to enable LDOs on init
rather than on probe.
VDD is set to LPM to support VDDMIN on when the PHY
is suspended.
Add ref clock which is routed to this PHY wrapper
and needs to be enabled for proper functioning.

Change-Id: Ic27404627501f14566bdfee0cb89a43e8d93dc50
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>