usb: dwc3: Fix connect/disconnect USB host issue

The original problem of connect/disconnect device in host mode.
Cable connect/disconnect is working, however any consequent
device plug out/in,  device is not recognized and the core
doesn't go back to LPM.
This is caused due to incorrect sequence of entering LPM.
Sequence is fixed accordingly.

CRs-fixed: 688823
Change-Id: I96f1e08a01fbc4bf71322c625bc16cd7784abc9a
Signed-off-by: Lena Salman <esalman@codeaurora.org>