Fix USB device-fixup warning "node not found". This was occuring
because of static nature of start_offset variable
Static start_offset was storing offset of last node modified, and
was becoming issue if node fixup is carried multiple times,
resulting in "node not found" warning
Signed-off-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>