staging: wilc1000: switch printks to vsprintf IPv4 extension

Switch printks with IP addresses to use vsprintf extension %pI4.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Luis de Bethencourt <luis@debethencourt.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>