fs: nfs: pick up network interface bootargs parameter
This adds the linux.bootarg device parameter from the network device of
the current nfs connection and adds it to the nfs bootargs line.
This allows booting from nfs without manually setting a ip=dhcp or
ip=<ipaddr> option.
Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>