dynamic_debug: make dynamic-debug supersede DEBUG ccflag

If CONFIG_DYNAMIC_DEBUG is defined, honor it over DEBUG, so that
pr_debug()s are controllable, instead of always-on.  When DEBUG is
also defined, change _DPRINTK_FLAGS_DEFAULT to enable printing by
default.

Also adding _DPRINTK_FLAGS_INCL_MODNAME would be nice, but there are
numerous cases of pr_debug(NAME ": ...), which would result in double
printing of module-name.  So defer this until things settle.

Cc: David Miller <davem@davemloft.net>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0eac07c..f486f63 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2687,14 +2687,14 @@
 #define MODULE_ALIAS_NETDEV(device) \
 	MODULE_ALIAS("netdev-" device)
 
-#if defined(DEBUG)
-#define netdev_dbg(__dev, format, args...)			\
-	netdev_printk(KERN_DEBUG, __dev, format, ##args)
-#elif defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG)
 #define netdev_dbg(__dev, format, args...)			\
 do {								\
 	dynamic_netdev_dbg(__dev, format, ##args);		\
 } while (0)
+#elif defined(DEBUG)
+#define netdev_dbg(__dev, format, args...)			\
+	netdev_printk(KERN_DEBUG, __dev, format, ##args)
 #else
 #define netdev_dbg(__dev, format, args...)			\
 ({								\