neighbor: remove definition of DEBUG

Defining DEBUG should only be done in development.
So remove DEBUG.
Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20210114212917.48174-1-trix@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/neighbour.c

@@ -41,7 +41,6 @@
 
 #include <trace/events/neigh.h>
 
-#define DEBUG
 #define NEIGH_DEBUG 1
 #define neigh_dbg(level, fmt, ...)		\
 do {						\