usb: phy: qusb: Update initialization sequence for emulation

Read target specific phy register offset and value to program
phy from rumi device tree. This prevents overwriting the phy
programming sequence in qusb phy driver for a particular emulation
target.

Change-Id: If2ede416688802c7e3d5607b0d4889f677e9253b
Signed-off-by: Devdutt Patnaik <dpatnaik@codeaurora.org>