usb: dwc3: Reset and initiate lpm while booting up with no usb cable

Reset and initiate controller and phy low power mode to bring them to
known good state during boot up. This will avoid any leakage and makes
sure that DP/DM lines are in high-z state.

Change-Id: I55dbe8d42ce9e56046bd7c99e17c2ec6f368c9a6
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>