ipconfig: Tidy up reporting of name servers

Commit 5e953778 ("ipconfig: add
nameserver IPs to kernel-parameter ip=") adds the IP addresses of
discovered name servers to the summary printed by ipconfig when
configuration is complete. It appears the intention in ip_auto_config()
was to print the name servers on a new line (especially given the
spacing and lack of comma before "nameserver0="), but they're actually
printed on the same line as the NFS root filesystem configuration
summary:

  [    0.686186] IP-Config: Complete:
  [    0.686226]      device=eth0, hwaddr=xx:xx:xx:xx:xx:xx, ipaddr=10.0.0.2, mask=255.255.255.0, gw=10.0.0.1
  [    0.686328]      host=test, domain=example.com, nis-domain=(none)
  [    0.686386]      bootserver=10.0.0.1, rootserver=10.0.0.1, rootpath=     nameserver0=10.0.0.1

This makes it harder to read and parse ipconfig's output. Instead, print
the name servers on a separate line:

  [    0.791250] IP-Config: Complete:
  [    0.791289]      device=eth0, hwaddr=xx:xx:xx:xx:xx:xx, ipaddr=10.0.0.2, mask=255.255.255.0, gw=10.0.0.1
  [    0.791407]      host=test, domain=example.com, nis-domain=(none)
  [    0.791475]      bootserver=10.0.0.1, rootserver=10.0.0.1, rootpath=
  [    0.791476]      nameserver0=10.0.0.1

Signed-off-by: Chris Novakovic <chris@chrisn.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>