usb: phy: Perform USB2 OTG PHY initialization before DWC3

DWC3 glue drivers may want to operate in OTG mode and
register USB OTG PHY only if one doesn't exist already.
Allow this by letting USB2 PHY driver register OTG PHY
first so that USB3 DWC3 glue driver find it available
later and safely assumes that it should run in host
only mode with USB2 running as OTG.

Change-Id: Icce25910f9bb39924f33b0b5bd38b963661e1431
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>