wanmain: comparing array with NULL

[ Upstream commit 8b72ff6484fe303e01498b58621810a114f3cf09 ]

gcc really should warn about these !

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>