ipconfig wait for carrier

v3 -> v4: fix return boolean false instead of 0 for ic_is_init_dev

Currently the ip auto configuration has a hardcoded delay of 1 second.
When (ethernet) link takes longer to come up (e.g. more than 3 seconds),
nfs root may not be found.

Remove the hardcoded delay, and wait for carrier on at least one network
device.

Signed-off-by: Micha Nelissen <micha@neli.hopto.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>