netfilter: Use LOGLEVEL_<FOO> defines

Use the #defines where appropriate.

Miscellanea:

Add explicit #include <linux/kernel.h> where it was not
previously used so that these #defines are a bit more
explicitly defined instead of indirectly included via:
	module.h->moduleparam.h->kernel.h

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/ipv4/netfilter/nf_log_ipv4.c b/net/ipv4/netfilter/nf_log_ipv4.c
index 7510198..076aadd 100644
--- a/net/ipv4/netfilter/nf_log_ipv4.c
+++ b/net/ipv4/netfilter/nf_log_ipv4.c
@@ -5,8 +5,10 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
 #include <linux/skbuff.h>
@@ -26,7 +28,7 @@
 	.type	= NF_LOG_TYPE_LOG,
 	.u = {
 		.log = {
-			.level	  = 5,
+			.level	  = LOGLEVEL_NOTICE,
 			.logflags = NF_LOG_MASK,
 		},
 	},