Always we use type unsigned long to format the ip address, since the
value of ip address is never the negative.

This patch uses type unsigned long, instead of long, to format the ip
address. The code is more clearly to be viewed by using type unsigned
long, although it is correct by using either unsigned long or long.

Link: http://lkml.kernel.org/r/1436694744-16747-1-git-send-email-mhuang@redhat.com

Cc: Minfei Huang <mnfhuang@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>