ipacm: get usb_link_up from usb-driver

Made the change to get usb_link_up from
usb-driver instead of using netlink
event to resolve the timing issue
between usb-driver and android framework.
Also not self-posting the usb-up from
downstream event which was used to support
ipcam restart phase 3.

Change-Id: I3549cfbfbb5f41fa5ed99a43f00c6d8b4333b8e5