While android initialization scripts typically set up the usb serial number,
it might happen at wrong time from usb-moded point of view and we in general
want to minimize the amount of android init that is needed/used for running
sfos.

Use usb serial number parsed from kernel command line when initializing
default usb properties.
Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>