usb: phy-msm-qusb-v2: Use phy autoresume register offset from device tree

Phy auto resume register offset may change with every target. Hence read
this register offset from device tree.

Change-Id: Ibbdb14eb6c8510b422161959c1978864b19360dc
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>